Patent Publication Number: US-2015072330-A1

Title: Electronic textbook

Description:
FIELD OF THE INVENTION 
     Preferred embodiments of the invention are directed towards electronic textbooks and other collections of useful information. In particular, preferred embodiments of the invention are directed towards creation and use of such collections of useful information, by permitting interested parties to traverse and annotate the collection of useful information, and recording the traversals and annotations for the benefit of other interested parties. Other preferred embodiments of the invention are directed towards aiding a creator&#39;s thought process when developing and communicating useful collections of information. One purpose of the invention is to aid productive thought by facilitating more accurate understanding and more effective communication. 
     BACKGROUND OF THE INVENTION 
     Limitations of Traditional Printed Books 
     In today&#39;s modern world, there is a vast ocean of information available on subjects of interest to users. This information is difficult to collect, organize, and present to users in a manner that is both focused and flexible. For example, publishing a collection of information in a book allows the book&#39;s author to present a focused presentation of the material, in a given order defined by the pages of the book. However, a book is not flexible. There is only one linear path through the book from start to finish, as defined by the book&#39;s author. Furthermore, if a user wishes to explore content outside of the book, there is no easy way for the user to identify appropriate additional content to explore, with any level of detail. This is particularly the case where the user wishes to explore additional content that was created after the book was written. Also, the user has no easy way to record that additional content for later consideration, either by her/himself or by others. 
     Limitations of the Web: 
     Alternatively, information may be published as a collection of separate pages, containing links from one page to another, such as Internet web pages. Information published in this manner is much more flexible, as a user can navigate through the information following the links between the pages. Also, web content is frequently updated, so later created additional content is made available to users. However, there is little organization to web content. It is difficult for a user to locate useful related content, if that content is not directly linked to from the page the user is reading. 
     Limitations of Usual Web Browsing Methods: 
     It is also difficult if not impossible for the user to gain the benefit of the experiences of others who have navigated through the same collection of information. At best, the user is presented with a page having links to other pages, but the user has no understanding of how other users have navigated through those links, why a particular user selected a particular link or path, or what path a particular user chose to follow through a collection of information. 
     It is also difficult for the user to make a record of the user&#39;s own navigation through the content, and to present that record to others. It is also difficult if not impossible for a user to provide additional content and link that content to the visited content. Users are not generally permitted to modify the content of web pages to add additional links. While users can create their own pages and provide links to the visited content, such links are only associated with the user&#39;s own page, and are not accessible from the visited content. Consequently, although a group of web pages might well represent a useful collection of information, it is difficult for users of the web to individually or collectively shape such a collection into a coherent whole. 
     Limitations of Printed Textbooks: 
     Notes have traditionally been taken on paper—sometimes on the pages of the textbook, sometimes on other sheets of paper. Each approach has its own merits and demerits. A traditional textbook cannot offer a multi-faceted note-taking system in which notes are directly associated with specific locations in the text, and yet also independently accessible and sharable. 
     In a traditional textbook course material is linear: search applies only to indexed items and is somewhat awkward; review of previously read material depends on the outline, notes and memory; and looking ahead must depend on the outline. Printed textbooks rely on the linear presentation of material, as set forth in the outline, and generally have difficulty presenting multiple parallel themes or discussing the interacting effects of multiple factors. The linear structure of both outline and material helps to maintain a single progression that aids our memory, but the linear structure does not always foster understanding and can subtract from understanding by de-emphasizing interrelationships among topics. 
     A printed textbook offers limited capabilities for students, teachers and others to share information. The student usually reads the textbook independently, and there is no way for teacher, fellow students, parents or mentors to supplement the student&#39;s reading experience effectively with timely and focused encouragement, elaboration, supplementary exposition, cautions (mistakes to avoid) or emphasis (things to focus on). 
     Thus there is a need to embed textbooks in an overlay setting that permits note-taking, handles richer non-linear outlines and multiple themes, and search; opens up this overlay to contributions by the student, the teacher, parents and others; and supports information sharing. 
     Limitations of Printed K-12 Textbooks: 
     Printed textbooks must be designed for a “typical student”, and cannot cater to the diverse needs of a varied student body. Since it is ordinarily not practical for students in the same class to use different textbooks, a textbook designed for the typical student forces classes to focus on the typical student. When major distinctions among students exist, the only practicable solution is clumsy and costly: different classes with different textbooks, such as special education with remedial textbooks, college-oriented classes with advanced textbooks, and special classes for students who speak a foreign language at home. 
     Diverse students would surely benefit from diverse materials to suit, but there is no practical way to assemble diverse material into a single book; printing costs would go up, books would get heavier, students and teachers alike would be confused, and there would be no way to administer personalized exams to reflect a student&#39;s unique status. Our education system shows clear signs of stress as a result: For example, the success of specialized schools catering to advanced students in some larger urban areas, in which the typical student is atypically advanced, strongly suggest that school systems that lack such facilities cannot now give their advanced students the full range of opportunities. Our education system also does not do well when educating students who have problems with standard textbooks due to issues like dyslexia or innumeracy, and yet possess ordinary or even superior intelligence. Such students may be able to understand the meaning and function of language and mathematics just as well as typical students, but do not readily comprehend symbolic representations in letters and numbers. They might learn much more through teaching methods that emphasize intuitive knowledge of the uses of language and mathematics, and allow the student to recognize the meanings that are implicit in those uses through experience rather than by rote learning. Such teachings, oriented toward meaningful understanding, might also be useful supplements for all students, but they cannot now be readily assimilated into standard textbooks. 
     The root of the these difficulties lies in the limitations of the printed, one-book-suits-all textbook: there is a need for a new form of textbook that offers each student a personalized learning opportunity embedded within a single overall consistent design. It is also clear that diverse student learning experiences arising from such a multi-functional textbook could cause confusion in the classroom—both between students and teachers and among students, so it will be important for the new form of textbook to be able to pass on student experiences and comments to the teacher and provide a framework for students to share their experiences with one another. 
     Thus, there is a need for a new way to organize collections of information such as electronic textbooks, in a manner which permits textbook authors or users to define different paths through the information, and which retains these paths, and information about these paths, allowing them to be made available for the benefit of other users. 
     Color-blindness shows up another limitation: the colors used in diagrams and figures in printed books are designed for the student with typical vision, and cannot be personalized for each color-blind student to a palette that best conveys information to their visual sensitivity. Thus, there is also a need for a new form of textbook that can morph the color palette in its diagrams to respond to the requirements of a color-blind student, which could therefore also be responsive to the personal color preferences of all students. 
     Beyond these evident limitations, there is a wider issue that impacts every student: we are all different and it is not clear that we should be forced onto a single path by a typical-student text. We will learn to understand the subject matter better while also learning more about ourselves when we are able to choose among various modes of learning and optional supplements, while receiving the guidance that we need from the textbook to make informed choices among them. Thus there is a need to develop an electronic textbook that provides these capabilities. 
     Limitations of Printed College &amp; Post-Graduate Textbooks: 
     In addition to the above limitations, printed textbooks in higher education present problems in the areas of cost and obsolescence, presenting complex knowledge in depth, linking up with other sources of information, fitting efficiently into a wider curriculum, and carrying knowledge forward after graduation: 
     Cost and Obsolescence: 
     The high cost of printed textbooks for higher education, estimated at $1,200 for the 2012-2013 academic year for College education in the United States, merits attention. The high pace of obsolescence in textbooks forces down the value of used textbooks, thereby increasing cost of ownership for students who resell, and calls into question the lasting value of books students purchase for their personal libraries. The lag time that often postpones publication until well after the author completes work is another concern in a setting of rapid obsolescence. It makes sense to shift to an alternative method of providing textbooks that hastens publication, reduces production costs and permits regular updates to existing textbooks. 
     Presenting Complex Knowledge in Depth: 
     The decentralized global research enterprise and the proliferation of shared knowledge on the web are overwhelming the adaptive capabilities of education based on printed textbooks. Linear outline and linear page sequence are the joint organizing principles of a printed book. Of course a book can also offer one or more separate lists of specialized items like figures or exercises to supplement the outline. However, there is no systematic means for rendering relationships between topics that cut across different segments of the outline. Nor is there any good way of highlighting the collective importance of relationships or themes that spread across different segments. Nor is there any good way of navigating through the book to see only those sections that deal with a single theme in the proper order. The tools presently available in a printed textbook to present complex material and promote understanding of complex matters are essentially limited to interpolated comments and diagrams, themselves trapped in the linear sequence of the book and visible only at that one point. Thus, there is a clear need for an electronic textbook that is built around the concept of a fully general non-linear outline that can make visible arbitrary relationships and present distinct traversal paths for each of the diverse themes presented in the book. There is also a need for an overlay system in the electronic textbook that allows faculty and students to add and share comments at any point in the book and fully general traversal paths through the book. 
     Curricula Involving Multiple Textbooks: 
     Inefficient cross-referencing between textbooks is a major drain on a student&#39;s energy and understanding in higher education. Everything would be much easier for students and faculty if textbooks could cross-refer effortlessly, and effectively interoperate. For example, most students in higher education regularly take courses in different but closely related disciplines, often for the purpose of assimilating interrelated knowledge, methods and perspectives, and many individual courses need more than one textbook to fully cover the material presented. However, at present there is no way for the printed textbooks to interact in a single curriculum, nor any way for faculty to effectively offer detailed traversal paths that could substitute for interaction. Thus there is a need for electronic textbooks that can be integrated in a common configuration, offering the student traversal guides that lead to mastery of their joint content. 
     Linking to References: 
     When reading a printed textbook, access to references is at best cumbersome. Nonetheless, it seems clear that one of the greatest potential values of a modern higher education textbook would stem from its usefulness as a superior access point to a vast and burgeoning literature. This service cannot be provided without offering the student direct access to the cited references. This service could well be a boon to authors and publishers, and readily achieved by an author, but will only be practicable when the textbook can be kept up to date at reasonable cost while continuing to offer direct and immediate access to current references. 
     “Direct Access” can be implemented to three degrees: access to the reference as a whole, or better direct access within that document to the point where the specific passage cited resides, or better still the added optional capability of native presence at the website serving the reference, beginning from the point where the reference resides, with the option of direct return at any time to point of departure. Thus, there is a need for an electronic textbook that can effectuate such access. Once electronic textbooks have this capability, it will become feasible for providers to service the referred materials to these degrees, allowing linking to a specific passage and optional native access when appropriate. 
     Fitting Efficiently into a Wider Curriculum: 
     The educational styles normally supported by a collection of linear printed textbooks do not accord well with the comprehensive perspective required for mastery of a curriculum by students and faculty. Although it is well known that many students benefit from both reading and hearing complex material, the higher education teacher is often required to devote lecture time clarifying issues with the textbook readings, filling in gaps in content, updating obsolete passages, and explaining other passages in greater depth. This is an awkward approach that is not fully satisfying for teacher or student, consumes valuable lecture time, and can create a sense of tension between lecture and textbook. In our changing world adequate textbooks do not always exist, and when the teacher develops supplementary readings to fill the gaps or extend available coverage, it is often difficult to coordinate the new material with the existing curriculum. Thus there is a need for electronic textbooks that are presented within the setting of an overlay that reflects the teacher&#39;s pedagogical requirements, allowing the faculty member to insert comments of all types, point out relationships, change the order of presentation, insert new material, and sometimes override elements of the material entirely. 
     A departmental faculty may work together to craft a consistent curriculum that integrates diverse textbooks and fills in the gaps, but there may be no efficient way to embody their efforts at the required level of detail in a form of documentation that can stand the test of time. Thus, there is a need for a general system that can serve as an umbrella above two or more electronic textbooks, guiding students through a curriculum that extends across them; assimilate supplementary materials provided by the faculty; and preserve superior teaching materials at the detail level in a lasting format. In such a general system, an overarching curriculum can be readily extended beyond the setting of a single course to cover an entire program. 
     Difficulties in Carrying Knowledge Forward: 
     Institutions of higher education are natural places for energy to be invested in organizing and integrating knowledge, and it makes good sense for them to build upon these efforts to provide lifelong educational services for their graduates. However, at present no efficient framework exists for the ongoing efforts of faculties in updating and expanding their knowledge base and curricula to be usefully disseminated to their graduates. The natural approach is a “living curriculum” in the form of overlay and supplementary material provided by the faculty that organizes and presents the information in electronic textbooks which are themselves being regularly updated. A setting of that kind could also shelter and support ongoing communications by faculty sharing their knowledge learned through experience to students and graduates in a relevant way. It would be quite possible for academic efforts of this kind, building upon electronic textbooks as their springboard, to become the foremost guides to professional information on the web. Thus, there is a need for an effective overlay system that integrates well with electronic textbooks and allows the fruits of ongoing collective faculty curriculum efforts to be shared with graduates as well as current students and regularly updated in a cost-effective way. 
     Urgent Need: 
     These challenges are intensifying. As society grows more complex and the pace of social change continues to accelerate, the gap between course content and application is widening. As more and more resources are freely available on the web and search providers become increasingly effective, the value added by an academic program is likely to diminish unless the program can assimilate the web as a resource included within its offerings. As knowledge deepens, increasing specialization requires a proliferation of classes, which in turn leads to smaller class sizes and higher costs per student. There is a compelling need for new educational tools built around electronic textbooks and overlays that can empower educators to offer the benefits of their understanding efficiently to their students in coursework and after graduation. 
     Need for New Methods and New Insights: 
     Like language, visual representation is a longstanding human skill. The two skills are complementary and have different strengths. It is time for us to coordinate language with map and diagram at a high level through computer displays based on innovative software. There is a need for techniques like the non-linear outline in the form of an overlay that blend language with visual representation. 
     Facing burgeoning complexity we need to look beyond the rigidly linear form of a printed book, which is rooted in the ancient tradition of memorization and subsequent recitation of spoken words. Linear thought does have limitations: It is easy to get caught up in a confined pattern of repetitive thought. By contrast, visual analysis takes us almost effortlessly to the big picture. There is a need for techniques like overlay and logic views that allow the visual field to assist in clarifying complex meanings. 
     Verbal analysis and visual analysis are two distinct mental capabilities. It is time to step away from predominant reliance on verbal analysis and learn to bring these two into closer balance. There is a need for techniques like the “dwordle” exercise, “visual logic” and “drawing with meanings” that help us to learn how to coordinate these two capabilities in productive thought. As our knowledge deepens and extends, we face increasing complexity. It is time to work with systematic tools that allow us to bring the highest qualities of verbal and visual analysis to bear. There is a need for tools like the closely-coupled “display field” and “tabular grid”, which represent complex material in both visual and verbal forms, and permit us to move at will between the two, seamlessly and spontaneously. 
     Requirement for Software: 
     The nodes and connectors in the electronic textbook have both verbal and visual qualities. The nodes are like titles in an outline, in the sense that meaning and texts are attached to them, but they are also like visible objects, in the sense that can be displayed in many different views in appropriate positions. The user soon appreciates their dual personality and expects them to magically behave as they do. Their intuitively straightforward behavior is accomplished by calculations performed by computer processes presented via displays projected by computer processes. There is a good deal of sophistication involved in the software that accomplishes this, which operates invisibly in the background to maintain a seamless user interface. 
     SUMMARY OF THE INVENTION 
     Basic Functions 
     In an aspect of an embodiment of the invention, an electronic textbook is presented as a collection of items of information with multiple navigation paths defined through the items of information. 
     In an aspect of an embodiment of the invention, each navigation path corresponds to a level of instruction, such as average, advanced or remedial. 
     In an aspect of an embodiment of the invention, materials from instruction levels other than the user&#39;s assigned level are optionally available to the user. 
     In an aspect of an embodiment of the invention, users are offered the choice of either or both of two different styles: conceptual/factual and cookbook-solution/procedurally oriented contrasting to meaningful/visual-tactile/understanding-oriented. 
     In an aspect of an embodiment of the invention, test-your-skills exercises are offered to student users, performance is evaluated, and feedback is given to the student. 
     In an aspect of an embodiment of the invention, users are offered the choice of teaching materials in three forms: written, spoken and video. 
     In an aspect of an embodiment of the invention, the user&#39;s choices concerning level and/or style and/or spoken/written and/or performance on test-your-skills exercises are recorded and analyzed to determine which personalized options should be visible to and recommended to the user. 
     In an aspect of an embodiment of the invention, users are guided and permitted to change paths while navigating through the textbook. 
     In an aspect of an embodiment of the invention, the user&#39;s recorded choices and/or test-your-skills performance are made available to privileged users such as parents, instructors, school authorities, authors and publishers in appropriate forms. 
     In an aspect of an embodiment of the invention, complete user paths through the textbook are recorded, with comments, for presentation to privileged users or other users. 
     In an aspect of an embodiment of the invention, privileged users and/or users are permitted to add additional content to the textbook. 
     Functions Serving Both User and Author 
     In an aspect of an embodiment of the invention, users of the electronic textbook benefit from a non-linear outline interconnecting the items in the form of an overlay in multiple layers. 
     In an aspect of an embodiment of the invention, the author of the electronic textbook organizes the material for the textbook using a similar overlay. 
     In an aspect of an embodiment of the invention, users of the textbook are able to access and extend the non-linear outline in either of two formats: a display field or a spreadsheet-like tabular grid. 
     In an aspect of an embodiment of the invention, the author of the electronic textbook conceives of and assembles the material for a textbook using the display field and tabular grid. 
     In an aspect of an embodiment of the invention, the electronic textbook user reviews the path already traced and explores options ahead in the display field. 
     In an aspect of an embodiment of the invention, the author of the electronic textbook uses the same display field to design and test navigation paths and optional choices for users. 
     In an aspect of an embodiment of the invention, users are permitted to use the display field and tabular grid to make personal notes on the items in the electronic textbook and create connectors among these notes, for their own benefit or the benefit of others. 
     In an aspect of an embodiment of the invention, the author uses the display field and tabular grid in the same way to create the non-linear outline overlay that determines the navigation paths and options 
     In an aspect of an embodiment of the invention, users work in the display field to include diverse audio and visual media in their notes on items in the electronic textbook. 
     In an aspect of an embodiment of the invention, the author uses the display field and tabular grid to assemble various audio and visual elements into the electronic textbook. 
     In an aspect of an embodiment of the invention, the electronic textbook user employs the glossary to find the meaning of a term, and then uses the display field to view selected highlighted instances of the term sought. 
     In an aspect of an embodiment of the invention, the author uses a list of terms in the tabular grid to sharpen up language and develop a glossary, and uses the display field to view selected other instances of terms under consideration. 
     In an aspect of an embodiment of the invention, the user&#39;s understanding is heightened by links between items in the display field that demonstrate logical relationships—“visual logic”—or suggest important associations—“drawing with meanings”. 
     In an aspect of an embodiment of the invention, the author uses visual-logic and drawing-with-meanings tools to explore complex interactions and elicit new ideas while simultaneously developing material for the electronic textbook 
     In an aspect of an embodiment of the invention, the electronic textbook user adds additional items to the electronic textbook using the display field and tabular grid and offers these to a privileged user or the author for inclusion in the textbook. 
     In an aspect of an embodiment of the invention, the privileged user or author reviews the material suggested by the user, deems it worthy of inclusion, and uses the display field and tabular grid to incorporate it into the electronic textbook. 
     Updates: 
     In an aspect of an embodiment of the invention, updates to the electronic textbook are made available to new purchasers and existing owners of the textbook. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The details of the invention, including structure and operation of the embodiments of the invention, may be gleaned in part by study of the accompanying figures, in which like reference numerals refer to like components. 
         FIG. 1  shows a collection of information nodes in an electronic textbook, according to an embodiment of the invention. 
         FIG. 2  shows paths associated with the information nodes in an electronic textbook, according to an embodiment of the invention 
         FIG. 3  shows additional connections between information nodes of an electronic textbook, according to an embodiment of the invention. 
         FIG. 4  shows a textbook reader, according to an embodiment of the invention. 
         FIG. 5  shows additional information nodes added to an electronic textbook, according to an embodiment of the invention. 
         FIG. 6  shows creation of a user-defined path through an electronic textbook, according to an embodiment of the invention. 
         FIG. 7  shows an embodiment of the invention, used to create an overlay for a collection of network-accessible pages of information. 
         FIG. 8  shows a browser add-on, according to an embodiment of the invention. 
         FIG. 9  shows an embodiment of the invention, used to create an overlay for a collection of content available in a digital library. 
         FIG. 10  shows an overlay builder, according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Certain preferred embodiments of the invention will now be discussed in detail. In an embodiment of the invention, with respect to  FIG. 1 , a collection of information is information for use in an electronic textbook  5 . An author compiles the information for use in the textbook  5 , and creates a collection of information items, or nodes  10 . For convenience, the nodes compiled by the author are labeled as “A-nodes” in  FIG. 1 . Further examples discussed below will introduce nodes  10  supplied by others who interact with the electronic textbook  5 . 
     Diverse Items: 
     Each node  10  contains a piece of information about the subject matter of the textbook  5 . For example, a node  10  can contain a sentence, a paragraph, a page, or a chapter of text. Additionally, a node  10  can contain multimedia information, such as a picture, a video recording, an interactive graphic, or a sound recording. The author can compile this information in a variety of ways. The author can create the information items in the nodes  10 , by for example writing the text, drawing the picture, or recording the video or sound. Additionally, the author can gather existing information items from other sources. The author gathers a text quotation from a source such as a book, or a historic document. The author samples a sound recording of a famous speech or dramatic performance. The author gathers a copy of a video recording made available to the author, such as a video of a presidential address, or of a historical event such as the Apollo moon landings. In an embodiment, each of the information items in the nodes  10  is selected by the author for inclusion in the electronic textbook. Additionally, as discussed in further detail below, other entities or individuals also select information items for inclusion in the electronic textbook  5 . 
     Comments on Items: 
     The author additionally provides comments about the information item. For example, the author describes why the author decided to include the information item in the electronic textbook  5 . The author identifies a source for the information item. The author may also indicate the date the author collected the information, or the date the author added the information to the collection. These comments may be included in each information item itself, or may be associated with an information item as attributes of the information item. The comments are associated with each information item, for example by being attached to or linked to the information item. 
     User Interactions: 
     The electronic textbook format allows the author to (i) attach interactive support functions to all nodes, and (ii) to embed within specialized nodes extensive interactive content. Further, (iii) the electronic textbook allows the interactions with the user to be recorded as attributes of the user&#39;s path through the electronic textbook that can be shared with friends, parents, teachers, the author, and so on, thereby serving a number of important functions such as guiding the user toward choices that result in finding their optimal book; tracking the user&#39;s use of the book and performance with material in the book, and sharing this information with parent and/or teacher; giving the student an opportunity to share comments and questions with other students and offer them suggestions about nodes to visit in the book. 
     Interactive Support Functions: 
     Interactive support functions include, for example: view-ahead, path-taken, perspectives, and overlay view (overlay view displays the network of overlays, including the user&#39;s, parents&#39;, teachers&#39;, friends&#39; with the option to focus on a subset such as just one&#39;s own comments), other navigation tools, search, index, and a number of dialogues. Examples of the dialogues include: “where am I and what can/should I do next?” dialogue, “where have I been and how can I review it?” dialogue, “I [don&#39;t understand, am confused by, can&#39;t remember, don&#39;t see the use of, am bored by] this, so please help!” dialogue, “I&#39;d like to see further [advanced, remedial, procedural, contextual, inspiring, detailed] material about this.” dialogue, ‘I&#39;d like to see an [example, exercise, application, exposition, intuitive illustration] of this.” dialogue, “Is there another way of [explaining, solving, proving, understanding, applying, thinking about] this?” dialogue. These dialogues provide a structured display and response to commonly encountered situations for the users. The forms of specialized nodes include, for example: junctions (gateways, vestibules, galleries, logic views and simple junctions), test your skills, examples, exercises, and interactive Aids to Productive Thought (APT). Interactive APTs are interactive displays that help to align conceptual and intuitive understanding, make useful connections between related topics, assist in remembering and getting a feel for things, help with the creative process and help with effective inference. 
     Querying Incomprehensible Passages 
     For example, in an embodiment, the electronic textbook encourages the user to select any sentence or passage that is difficult to understand, and drag and drop it into a query window. The electronic textbook may then request that the user read the section through completely and then read through to this point a second time before actually launching the query if the passage is still not clear. Once the query is launched, the electronic textbook presents an explanation to the user, which is drawn from a combination of glossary entries, remedial material, and special exposition designed exactly for that passage. In this embodiment, users difficulties with particular passages are reported back to the author or publisher, allowing for the database of special expositions to be expanded and potentially leading to rewriting of unclear passages. In this embodiment, the electronic textbook is likely to be frequently updated. Updating would be transparent to users on the cloud, and users who downloaded the textbook to local computers would receive update downloads. Returning to the experience of the user, the electronic textbook asks the user after reviewing the expository material whether the passage has become clear. If not, the user is offered the choice of attaching a query comment to guide parent, teacher or other mentor to provide assistance later on. 
     Study Partner: 
     As another example, in an embodiment, the Study Partner is an audio presentation that interacts with the student user verbally. Study Partner presents himself/herself as the student&#39;s peer and makes the process of study more engaging. Study Partner can interact with the student user at any time. For example, it can administer an exercise or test your skills exam in friendly dialogue, carrying out all of the steps from introducing the exercise/test, offering feedback along the way, and concluding with a discussion about how the student&#39;s performance fits in with the student&#39;s study plans and longer term goals (see below for more information on study plans and goal setting). Study Partner can receive queries and present responses in dialogue, voicing prepared query-response passages, the content of glossary entries or recommended references. Study Partner can activate any aspects of navigation through the overlay on behalf of the user, guiding the user to remedial material or inviting the user to consider more advanced material that comes up in the dialogue. Study Partner can also drill the student user on study material, offering additional explanations or alternative approaches. Study Partner can convey new information to the student user, such as informing the student user of the arrival of new comments by other users. In order to function, Study Partner depends on three primary elements. First, it draws upon content provided by the author and publisher—including the basic content of the electronic textbook and additional material developed for query response—as well as content assimilated through the contributions of the school and teachers, parents and mentors, the student user, and fellow students. Second, Study Partner relies on the logical structure for this content embedded in the Electronic Textbook, including the layout for query response, in order to provide the benefit of this store of information to the user in a friendly and supportive way. Third, Study Partner relies upon capabilities for voice recognition and intelligent dialogue that are familiar in consumer electronics applications such as Siri and well known in the industry. 
     Notes, Comments and Reminders: 
     In an embodiment student users are able to attach a note, comment or reminder at any node or connection in the electronic textbook, including any nodes or connections that have been added by the user. As these terms are used here, a “note” is directly related to the electronic textbook and explains it in the user&#39;s own words; a “comment” is anything else that is relevant, and particularly something that is intended to be shared with others or describes the user&#39;s experience; and a “reminder” is a personal memo to oneself, usually something that is ongoing and needs to be recalled afterward. A note may or may not be shared with others, as determined by the user or arranged by other privileged users. A comment is more likely to be shared, and in some embodiments may be shared by default within the user group. A reminder is private by default, although it can be shared with selected other users. The user can view his or her own notes, comments, and reminders along with the node or connection to which they are attached, and these can also be viewed in a gallery filtered and/or sorted by location, topic or time created, and can also be located by searching for any term. Notes, comments and reminders can be created with Voice Memo for audio or Video Memo for video, and can also be typed as text in the Text Memo field. 
     Aids to Focus and Time Management: 
     In another embodiment, the electronic textbook can highlight for the student user the time span of the present study session, recording the start time and asking the student for the planned duration. The electronic textbook can then offer to disable the internet during study sessions. It can prompt the student when no evident user activity occurs during a 5-minute interval or whenever scope is switched away from the textbook during the session. The electronic textbook can alert the student to the amount of time seemingly diverted to the internet or other activities during the study session, and report both “clock time” (the duration of the session), and “study time” (the estimated time actually invested reading and interacting with the material.) 
     Multiple Paths Through the Book: 
     Turning to  FIG. 2 , the author defines a number of paths that traverse through the nodes  10 . These paths are made up of connections  7  between the nodes  10 . The connections  7  of an embodiment can be as content-rich as the nodes  10 , rather than merely serving as connections between the nodes  10 . A path comprises a series of connections  7  in addition to the nodes  10  that they connect, and much of the information that pertains to a path is associated with the connections. For example, many author or user notes and comments naturally attach to connections  7 , not to nodes  10 . Such comments include explanatory comments clarifying why a particular connection was traversed, or previewing what the user can expect to encounter in the node  10  at the other end of the connection. The traversal record that constitutes a path comprises connections. Connections have attributes that aid in navigating through the electronic textbook  5 . 
     Connections of Various Types: 
     For example, if a user is surprised by a node  10  or otherwise wishes more information about how the user arrived at the node  10 , the comments and other attributes of the connections  7  allow the user to find out where he is, and where he came from. Connections  7  also possess attributes. This is important because in many applications, various connections  7  serve more than one function or role, and it is sometimes important to separate out or highlight connections  7  based upon their role. For example, some connections  7  connect a sequence of nodes  10  and some connect branches to that sequence, while others reflect logical relationships. Some may represent a person&#39;s comments or additions, as distinct from those provided originally by the author. The connections  7  allow the functions they serve to be identified as attributes that aid in making informed choices and displaying the map of the electronic textbook  5 . 
     Average, Advanced and Remedial Paths: 
     Each path represents a different presentation ordering for the instructional material used in the electronic textbook  5 . For example, in this embodiment the electronic textbook  5  includes a primary path  12 , which represents the path an average student is expected to take through the electronic textbook  5 . The electronic textbook  5  further includes an advanced path  14 , which represents the path an advanced student is expected to take through the same electronic textbook  5 . The electronic textbook  5  further includes a remedial path  16 , which represents the path a remedial student is expected to take through the same electronic textbook  5 . 
     Written, Spoken and Video Formats: 
     Additionally, the author can define paths that take into account additional desired instructional techniques. For example, some students process audio or visual information more efficiently than textual information. For these students, the author can provide alternative nodes  10  which present the same instructional content in different forms. Thus an item of instructional content may be provided in narrative text form in one node  10 , in audio form in another node  10 , and in image or motion picture form in yet another node  10 . Additionally, the author can provide alternative nodes  10  which provide the instructional content in different languages, either textual or spoken. Alternatively, a given node  10  may present the same content in multiple different forms. A user traversing a path in the electronic textbook  5  will then select the form of information which the user finds most efficient to process. Of course, the form of information selected by the user can vary from node to node. 
     Individual Paths are Distinct: 
     Each of the paths  12 ,  14 ,  16  traverses through the nodes  10  of the electronic textbook  5 . The paths  12 ,  14 ,  16  may each traverse different nodes  10 , or the paths  12 ,  14 ,  16  may overlap one or more nodes traversed. For example, in  FIG. 2  the path  12  and the path  14  each traverse the node  10   a . The node  10   a , therefore, represents an information item that is expected to be helpful both to average and advanced students traversing the electronic textbook  5 . In an embodiment, the paths  12 ,  14 ,  16  are independent of each other, unless the author creates a connection between the paths. Thus the particular connections  7  between the nodes  10  can be members of multiple different paths. The connections  7  can be combined into a path without concern about the connections&#39; roles in other paths they may belong to. All paths to which a connection  7  belongs are separately stored. The membership of a given connection in the various paths of the electronic textbook  5  is an example of one of the attributes of a connection. 
     Informed Choice: 
     Having defined multiple paths through the nodes  10 , it is helpful to provide the user with a variety of ways to choose amongst the paths, or to make other choices which will enhance the user&#39;s educational experience. Among the important concepts reflected in embodiments of the invention is the concept of informed choice. The term “informed choice” refers to the tools and techniques that the electronic textbook  5  offers to assist the user in finding the appropriate path. It is beneficial for the electronic textbook  5  to give the user a wide variety of choices of ways to navigate through the material reflected in the nodes  10 , and to give the user the information necessary to make wise choices. The framework of the electronic textbook  5  emphasizes meeting individual wishes and needs by offering diverse paths and helping users to find their appropriate path. 
     Learning about Knowledge: 
     The framework of the electronic textbook  5  facilitates creative development, learning and teaching. While helping people to learn the subject matter at hand, it also helps them to learn more about their own state of knowledge and to clarify their thoughts. The framework encourages users to reflect on how the electronic textbook  5  can assist them. For example, at a significant point along the paths through the electronic textbook  5 , a user might see among the options presented in a node  10  such responses to choose as “Why am I doing this: what&#39;s in this for me? Can you make this more interesting? More relevant. I need an example! I&#39;m completely lost. I disagree with this. I&#39;m interested; can you tell me more about this? Go into this more deeply? 
     Dialogues: 
     Here are some further examples of dialogues that an author might offer to a user: 
     Where am I and what can/should I do next? 
     Where have I been and how can I review it? 
     I [menu: don&#39;t understand, am confused by, can&#39;t remember, don&#39;t see the use of, am bored by] this, so please help! 
     I&#39;d like to see further [menu: advanced, remedial, procedural, intuitive, contextual, inspiring, detailed] material about this. 
     I&#39;d like to see a [menu: example, exercise, application, exposition, intuitive illustration] of this. 
     Is there another way of [menu: explaining, solving, proving, understanding, applying, thinking about] this? 
     Please refresh my understanding of [list of topics from which to choose.] 
     Does this relate to [list of topics from which to choose]? 
     Setting Goals and Monitoring Progress: 
     In an embodiment, the electronic textbook can discuss goals with the student during informed choice dialogues. For example, the electronic textbook can suggest such goals for improvement as (i) doing well in the course and moving up from remedial to average, or from average to advanced; (ii) completing the course material early and going on to material in the subsequent course; (iii) going more deeply into intuitive understanding of what the material is useful for and how it works, and (iv) working through the material more quickly and efficiently. In brief, these four dimensions could be summarized as academic mastery, academic advancement, practical mastery and pace. 
     The electronic textbook can encourage the student user in various ways to respect the goals that they have set and to monitor their own efforts and progress. Once a substantive goal is formulated, the electronic textbook can propose a graduated series of intermediate steps that will lead to attaining the goal. If the student establishes a time-frame for attaining the goal, the electronic textbook can suggest reasonable target dates for completing the intermediate steps. The electronic textbook can offer the student to track their progress toward their chosen goal, and to give them advice and encouragement along the way. With the student user&#39;s agreement, the electronic textbook can offer supportive comments that compare the student user&#39;s actual progress with the targeted schedule. 
     Alternatively, if the student prefers, the electronic textbook can report on their accomplishments respecting all four goals. For example, the electronic textbook could help the student user to create a critical path to learning select material based on the user&#39;s input of number of hours to be spent per day, with specific goals for mastery of material achieved by a certain date. 
     In an embodiment, the electronic textbook analyzes each study session as the student user is winding it up, taking account of the student user&#39;s interactions including path taken, performance on exercises and test your skills, time spent on various features and queries launched, and self-evaluation comments. Placing this information into the context of the course syllabus and the user&#39;s expressed goals and experiences in prior study sessions, the electronic textbook can provide feedback to the student user and/or to the student&#39;s parents or teacher in an appropriate way. 
     Considering Options: 
     When the user selects one of these dialogues, the user is directed to a node  10  which provides information responsive to the choice the user made. Encouraging a user to choose invites the user to reflect on what the different possibilities mean to them and to consider how best to make a decision. Choices promote awareness of people&#39;s diversity, for people are different and make diverse choices. A user may choose options that fit their own interests, or they may select an option because they are interested in why it is interesting to others, or because it contradicts their views. 
     Information and Perspectives: 
     The electronic textbook  5  of an embodiment offers many types of information, such as: 
     Orientation—what path has been traced up to this point, what choices are there at this moment and where do they lead. 
     Comprehensive overview and search: a comprehensive list of available features and links, which can be filtered by any applicable attributes; 
     Recommendations optionally supported by comments, based upon the user&#39;s experiences so far; 
     “Test your skills” questions that yield recommendations on what more may be important to learn; and 
     Alternate paths provided by the author or friends. 
     Nodes for Navigation and Logic: 
     The nodes  10  and connections  7  in the electronic textbook  5  offer a range of options for giving the user choices to select from: 
     a Vestibule node displays the relevant choices when a user reaches a junction; 
     a Gateway node welcomes the newly arrived user to a path or introduces the user to a section; 
     a Gallery node shows a wide range of alternatives; and 
     a Logic View node presents causal relationships or associations, most often when items are interrelated in complex ways; 
     an ordinary junction (typically a connection, but it can be a node) offers a signpost with explanatory text as appropriate. 
     Halls of Informed Choice: 
     As will be discussed in further detail below, the electronic textbook  5  when viewed in an environment such as that presented in the reader of  FIG. 4 , presents a view-ahead window which shows the next stations on the present path, and a path-taken window showing the previous stations. All of these and more are referred to generically as halls of informed choice. 
     Halls of informed choice are offered at important junctions to present the author&#39;s customized discussion and display of the choices available. These halls supplement perspectives (discussed in further detail below), which are available at every node to provide local views or views of the entire document. Note that a hall is a component of the navigation aspect, and so has many functions in common with connectors, but it is a node dedicated to navigation rather than a connector. There are four main types of halls as well as ordinary junctions. 
     Gateway: 
     A gateway is an entry point to a path or section of the document. This may be designed for newly arriving visitors or for users transitioning to a new section. An electronic textbook  4  (or overlay  41  as discussed below) can have many gateways, each serving a different audience. Typically a gateway offers welcoming information, an introduction and a summary of what lies ahead, all of which may be tailored to the user&#39;s needs based on their prior path. A gateway can invite the user to consider opportunities and reflect on what might be most useful or appealing. 
     Vestibule: 
     The user generally enters a vestibule after having made a choice. Consequently a tool-tip introducing the vestibule may appear when the cursor is passed over that choice. Vestibules can have diverse purposes, such as to present a preparatory test of skills, offer an exercise, invite the user to pause and reflect, or summarize the material graphically in preparation for a further choice. 
     Gallery: 
     Generally a gallery displays nodes that have a common status. For example, all of the optional nodes in an electronic textbook might be displayed in a single gallery. Alternatively, all of the subtopics of a topic might be displayed in a gallery. 
     Logic Views and Logical Nexus: 
     A logical nexus can, for example, represent a special factor common to a number of nodes. In a book about society, for example, some distinct factors might be cooperation, personal accomplishment, knowledge, thoughts and emotions; each of these factors could be awarded its own logical nexus that presents the role that the factor plays throughout the book in a meaningful way. A logic view node could display many such logical nexuses, presenting a visual display of the role of each in the book and giving the user ready access to all this information. 
     Structural Views: 
     Some of the most important logic views are structural. A structural hall shows nodes according to some organizing principle. For example, nodes might be arranged in a two-dimensional table. In an electronic textbook, the columns might be different paths through the material, such as remedial, average and enhanced, and the rows might be lessons. Alternatively, nodes might be arranged in a circle or several concentric circles. Generally a logic view node is a visual element displaying logic and also serves as a staging area from which to quickly explore that logic, by navigating to the nodes  10  pertaining to the logical concept that relates the nodes together. 
     Ordinary Junction: 
     An ordinary junction generally does not have a special node attached. Instead it assembles and displays attributes of the connectors and their nodes that can be reached at that junction. It is like a signpost at a junction on a trail. 
     View Ahead and Path Taken: 
     Unlike the halls mentioned so far, which apply to fixed positions in the electronic textbook  5 , View Ahead and Path Taken accompany you on your journey, for example as stand-alone windows. Wherever you are, they show you the choices ahead of you and the path you have traced so far. 
     Entry Gateway: 
     Turning to  FIG. 3 , the author defines additional connections and nodes of the electronic textbook  5 , to implement the halls of informed choice discussed above. For example, the author can provide a variety of ways for the user to select a path to begin traversing the electronic textbook  5 . One way is to present a gateway node  10   a  having a series of test questions, which test the beginning skill level of the user. Based on the outcome of the test questions, the user is directed to the appropriate path. High-scoring users are directed to the advanced path  14 . Average-scoring users are directed to the average path  12 . Low-scoring users are directed to the remedial path  16 . 
     Alternatively or additionally, the user may be presented with each of the available paths, along with comments that explain each path. These comments can be stored as an attribute of the initial path connection. This connection attribute may be displayed to the user when the user expresses an interest in learning more about the path, for example by clicking on the path starting point, or by moving a pointer over the path starting point, or some other way of indicating an interest in learning more about the path. Alternatively, these comments can be set forth in the gateway node  10   a , which lists and explains some or all of the paths available in the electronic textbook  5 . To further aid in organization of the paths through the electronic textbook  5 , the paths may be presented in various orders. For example, author-defined paths are presented first, followed by paths created by privileged users such as teachers, schools, or school districts. Then paths created by other users are presented. The active path for a specific user can be presented before all other paths, to assist the user in picking up where the user left off in the textbook  5 . 
     Arrangement of Paths: 
     In an embodiment, the electronic textbook also permits arrangement, of paths, whereby only certain specified paths and options along those paths are permitted to a particular user, while other paths and options along the permitted path are securely hidden. Arrangement is an important feature of the electronic textbook that facilitates administration of the electronic textbook. The teacher can arrange the gateway node  10   a  so that the student begins on an assigned path, such as the average path  12 . Alternatively, if the student has studied with other electronic textbooks in previous classes, it can be arranged that the recorded performance of the student in those prior classes determines the options available in the gateway node  10   a.    
     Multiple Years of Instruction: 
     The information included in an electronic textbook need not be limited to a single grade or a single topic. For example, a single mathematics textbook might include all the instructional material for grades one through four. In this case, a student beginning the second grade would enter the gateway node  10   a  with the options of reviewing material from the first grade, beginning at the start of the second grade and beginning at the point where the student left off in the previous year if the student had already progressed into second grade material while in the first grade. 
     Multiple Themes: 
     As an another example, consider a college-preparatory class in U.S. History or Social Studies. An electronic textbook might be designed around a chronologically organized primary path, while also embedding in the primary and supplementary material nodes that typify different organizational approaches used in academic fields such as economics, social science, political science, law, ethics and psychology. The first part of a year-long course could be taught in a chronological way following the primary path, while the second part repeatedly returns to the gateway node  10   a  to traverse different academic themes one after another, reflected in different paths through the nodes  10  of the electronic textbook  5 . Thus, the electronic textbook of an embodiment offers the students useful perspectives on the choices available in college. Another instructor might present the material in the book in a more conventional way, integrating the supplementary material alongside the primary material as a year-long chronological course. 
     Extending and Updating: 
     While building the paths  12 ,  14 ,  16  through the nodes  10 , the author also can create additional nodes  10 , or refine or change the content of the existing nodes  10 , as desired. For example, in reviewing the instructional material, the author decides that the contents of a particular node  10   b  may be confusing to some students, or the students would otherwise benefit from additional explanation. The author therefore adds an additional node  10   c , such as a vestibule, which provides this further explanation, along with connections  12   b  from the node  10   b  to the node  10   c , and back again. Alternatively, the author decides to update the textbook  5  with additional information, such as a new version of the textbook  5 , to incorporate newly-discovered information. This additional information may also be added as additional nodes  10 . 
     Path-Dependent Navigation Options: 
     Note that node  10   c  may also be linked to by other nodes, such as the node  10   d  on the advanced path  14 . Similarly, node  10   k  is connected to nodes on both path  12  and path  14 . Where a node is linked from multiple other nodes, the electronic textbook  5  retains knowledge of the node from which the user came, and uses that knowledge to provide further options to the user. For example, if the author desires that the user stay on the same path  12 ,  14 ,  16  that the user was on, then for users who arrive at node  10   c  from node  10   b , the node  10   c  will present only the connection  12   b  back to node  10   b , and not the connection  14   b  to the node  10   d . Similarly, for users who arrive at node  10   c  from node  10   d , the electronic textbook  5  will present only the connection  14   b  back to node  10   d , and not the connection  12   b  to the node  10   b . Likewise, users who arrive at node  10   k  on path  12  will leave node  10   k  on path  12 , whereas users who enter node  10   k  on path  14  will leave node  10   k  on path  14 . This feature allows the electronic textbook  5  to use the same content on both paths  12 ,  14 , without risk of confusing the user as to which path the user is on. 
     Availability of Options: 
     Optionally, the user will not be presented with the connections on the path the user is not currently travelling. Alternatively, the electronic textbook  5  can present both return connections, and thereby allow the user to switch paths from the path  12  to the path  14  via the node  10   c  or  10   k . This is an example of a context-sensitive feature of the nodes  10 . The user&#39;s experience is different, depending on which path the user took to arrive at the node  10   c  or  10   k.    
     Test Your Skills: Path Transitions Based on Performance: 
     It is also advantageous for the user to be permitted to change paths, as appropriate for the user&#39;s skill level and understanding of the material. Thus the author builds in nodes  10  which facilitate the user&#39;s changes in path. For example, the author determines that at node  10   e , a user on the remedial path  16  should be offered a test, to see if the user has grasped sufficient knowledge to be elevated to the average path  12 . The author creates the test node  10   f , and prepares appropriate skill test material, such as test questions. If the user passes the skill test, then the user is elevated to the average path  12 , via the connection  16   b . If the user does not pass the test, then the user is returned to the remedial path  16 , via the connection  16   c.    
     In this example, the test is optional. After reviewing the content at node  10   e , the user is offered the opportunity to take the test at node  10   f , via the connection  16   a . As with any of the nodes  10  or connections  7 , the user may provide comments associated with the connection  16   a . For example, the user may explain why he elected to take the test, or offer words of encouragement to other users following the user&#39;s path. If the user declines the option to take the test at node  10   e , then the user continues to follow the remedial path  16 . 
     The electronic textbook  5  also includes nodes such as the node  10   g  on the advanced path  14 , where a test is incorporated into the content of the node. Here, the user is simply presented with the test. If the user passes the test, then he continues on the advanced path  14 . If he does not pass the test, then the user switches to the average path  12 , via the connection  14   a . Similarly at node  10   h , a user on the average path  12  is presented with a test. If the user passes the test, he is switched to the advanced path  14  via the connection  12   a . If the user does not pass the test, he continues on the average path  12 . The transitions from path  12  to path  14  are, in this example, seamless and transparent to the user. The user is only aware that he was asked test questions, and that he was then presented with a path to follow to the next node. Thus the user need not even be aware that he has been switched to a more difficult path, or to a less difficult one. 
     Information about Choices: 
     In addition to presenting test questions to the user, the electronic textbook  5  can also include other types of choices offered to the user, in nodes  10 . For example, as discussed above, at a significant point in the electronic textbook  5  a user might see among the options presented to them in a node  10  such responses to choose as “Why am I doing this: what&#39;s in this for me? Can you make this more interesting? More relevant. “I need an example! “I&#39;m completely lost. I disagree with this. “Please refresh my understanding of [list of topics from which to choose. “I&#39;m interested; can you tell me more about this? Go into this more deeply?. Does this relate to [list of topics from which to choose]. Based on the choices the user makes, the user will be directed to different nodes  10  in the electronic textbook  5 , such as nodes on a different path, or explanatory nodes to clarify difficult content. 
     Logical Connections: 
     The author can also include other ways to associate nodes  10  with each other in an electronic textbook  5 , without creating a path. For example, the author could determine that a node on the average path  12 , such as node  10   b , contains content that is logically related to another node, such as the node  10   i  on the remedial path  16 , or the node  10   j  on the advanced path  14 . Then the author creates a connection  12   c  with an attribute indicating that the nodes  10   b  and  10   i , or  10   b  and  10   j , are logically related to each other, even though they are on different paths. This attribute can be in a comment added to the connection, explaining the relationship between the two nodes. In an embodiment, the author creates the logical connection by dragging a connection between the node  10   b  and the node  10   i . The connection may be highlighted, represented with a dashed line, or otherwise marked to distinguish it from a connection that forms part of a path. This connection could be used by a student to optionally review the related content at nodes  10   i  or  10   j . Alternatively, it could be arranged that this connection would be obscured from display to students, and instead could be provided only to the author, or to privileged users of the electronic textbook  5  (e.g. teachers or school boards). Of course, these logical relationships can be defined between any nodes  10  which are logically related, regardless of which path  12 ,  14 ,  16  the nodes are on. 
     Knowledge Garden: 
     Just as a garden path offers the walker views of other features in the vicinity, a textbook of an embodiment can be designed as a “knowledge garden” with primary paths that the user must traverse, which are enriched by an array of relevant topics potentially interesting to the user offered optionally at each point along the way. In a knowledge garden, a gradually unfolding set of options may be displayed as a set of small icons from which to choose. For example, if there were 200 nodes along a primary path, there might be 500 supplementary nodes of this kind in the electronic textbook. The author would select a subset of six of these to appear as options on each primary node, selected from among the total of 500 for relevance and appropriateness. The connectors among these supplementary nodes can be thought of as the layout of the garden. 
     Structural Connections: 
     Another kind of relationship is “structural”. This is an important special case of logical relationships that arises when nodes fall into categories (related in sequence by type) or fall into a matrix structure like a table or spreadsheet. For example, language texts may cover a basic series of grammar topics each year, in which case the matrix would have grades as its rows and topics as its columns. Alternatively, the chapters of a text might contain text, examples, and exercises, leading to three categories. Also, the author may choose to cover exactly the same distinct topics at different levels (remedial, average, and advanced) or in different ways (procedural and intuitive), so that the topics are rows and the forms of coverage are columns. These special cases are important because they offer different modes of traversal and call for special display formats. 
     Other Connections: 
     Also there is the straightforward relationship arising from a glossary. Also there are, as explained below, possibly overlays provided by the teacher, or parents or the user&#39;s personal use, or by the user for his/her own use. 
     Perspectives: 
     The electronic textbook  5  of an embodiment also offers perspectives, which are representations of portions of the electronic textbook  5  that allow the user to explore outside the restrictions imposed by the author&#39;s own structure. Perspectives have many facets. A perspective can show, for example, the entire electronic textbook  5 , a given path  12 ,  14 ,  16 , the nodes  10  and connections  5  in the vicinity of a path  12 ,  14 ,  16 , or the connections between two paths. It can show your present location, or the possible paths leading from your location stretching out to a requested distance (either simply measured as a number of nodes out on the path, or using a distance metric such as those discussed with regards to visibility of a path below). It can show the path you have traced so far and the recommended path ahead. If you are interested in traversing from your present location to another node in an orderly way, alternate paths can be shown in perspective. (Of course you always have the alternative to just jump to a desired node, and you will often do so.) 
     A perspective can highlight any category of features (i.e. nodes) and/or any category of connections. It can show some or all categories, each highlighted in a different way. A perspective can also work with “layers”, which are like tiers in a “layer cake.” Layers may represent different stages of progression or different levels of the non-linear outline. The perspective can show them individually, alternately, or in progression like horizontal slices through the cake. It can also show them all at once as a three-dimensional image, while highlighting the different layers in a variety of ways to distinguish them. 
     Any hall of informed choice can display on request an appropriate perspective well suited for considering where to go next. Similarly, certain perspectives, such as the path ahead or path taken, can be continually displayed by the electronic textbook  5 , for example using the reader of  FIG. 4 , discussed below. 
     Perspectives can take diverse forms. Structure of the nodes  10  and connections  7  can be displayed graphically or can be implicitly shown through the form of a table. For example, orderly arrangements of nodes  10  or connections  7 , and their attributes, can be shown in a spreadsheet view in the tabular grid  61 . 
     Textbook Reader: 
     Turning to  FIG. 4 , the electronic textbook can be viewed using a textbook reader  21  running on the user&#39;s computer. This reader  21  may also be used by the textbook author to build the electronic textbook  5 , and may incorporate the features of the overlay builder  56  discussed in further detail below. The textbook reader  21  includes a content viewer  22 , which displays the content of the various nodes  10  of the electronic textbook  5 . The content viewer  22  permits the user to interact with interactive content, such as by clicking on words or images to navigate to, for example, a glossary as discussed in further detail below. If the content in the content viewer  22  itself contains connections to other content, the user can activate or navigate to that content by clicking on it. The content viewer  22  can additionally incorporate the functionality of the visual display  60  and tabular grid  61  as discussed in further detail below with reference to  FIG. 10 . This allows a reader of the textbook to experience the same benefits realized by the textbook author, which is particularly helpful where the reader wishes to extend the content in the electronic textbook  5  as discussed herein. 
     Path-Taken View: 
     The reader  21  also contains a path-taken window  23 . This window shows the path the user has followed thus far, to arrive at the node  10  displayed in the content viewer  22 . The path can be displayed either in text form, or preferably in graphical form as shown in  FIG. 4 . In an embodiment, the current node  10  being displayed is highlighted in the path-taken window  23 , for example by being bolded, with an arrow indicating that the content of the current node  10  is displayed in the content viewer  22 . 
     View-Ahead: 
     The reader  21  also includes a view-ahead window  24 , which shows the user the nodes  10  that are visible from the current node  10 . These nodes are also preferably displayed in graphical form as shown in  FIG. 4 , but may alternatively be displayed in text form, for example a list of nodes, or a two-dimensional spreadsheet view of nodes with their attributes in the tabular grid  61 . The view-ahead window  24  can display the connections from the current node  10  in different ways, depending on the nature of the connection. For example, sequential connections on the path  12 ,  14 ,  16  that the user is following are displayed with emphasis (e.g. bolded or solid lines), whereas logical connections to other nodes are displayed with less emphasis (e.g. dashed lines), and other visible nodes may be displayed with even less emphasis (e.g. grayed out). In the view-ahead window  24 , as well as in the path-taken window  23 , the user can access information about the nodes in these windows by, for example, moving a cursor over the node, causing information, such as a comment or summary of the node&#39;s content, or the location of the node, to pop up or be displayed in the textbook reader  21 . These are examples of the interactive support functions discussed earlier. The user can navigate to any node  10  displayed in either window simply by clicking on the node in the respective window  23 ,  24 . 
     Comment Window and Index Window: 
     The reader  21  also includes a comment view window  26 . This window displays comments pertaining to the current node  10 , and permits users to add or edit their comments. The reader  21  also includes an index window  27 . This window displays an index of terms in the electronic textbook  5 , for use as discussed herein by the user. 
     Navigation Tools Window: 
     Finally, the reader  21  includes a navigation tools window  28 . This window displays any tools used by the user to navigate the content in the electronic textbook  5 . This window  28  contains a search tool, for the user to search the electronic textbook  5 . The window  28  contains a global view button, which allows the user to display a graphical view of the entire textbook  5 , or alternatively those portions of the textbook  5  which are accessible or visible to the user (e.g. depending on the user&#39;s role, and the visibility metrics discussed above). The global view in an embodiment uses the display area  60  and the tabular grid  61 , discussed in further detail below with reference to  FIG. 10 . The window  28  contains an external content button, which allows the user to navigate to external content, not found in the electronic textbook  5 . As discussed in further detail below, this external content is accessed by the user and stored in the electronic textbook  5 . Finally, the window  28  contains an add comment button, which allows the user to add a comment to the current node  10 , or, when the user navigates a connection  7 , to that connection  7 . The windows of the reader  21 , may optionally be hidden from view and only displayed when selected, for example from a menu, by the user. 
     Navigation Information: 
     The electronic textbook  5  offers many types of information to users, while they are navigating the electronic textbook using the reader  21 . For example, the users are offered orientation information, showing the user what path has been traced up to this point, what choices are there at this moment and where they lead. The user is offered a comprehensive overview of the electronic textbook  5  and search capabilities to locate any desired content in the electronic textbook  5 . If the user identifies a particular node  10  in the electronic textbook  5 , the user is offered a selection of the various paths that the user could take to arrive at the identified node, from the node the user is currently at. Of course, in an embodiment the user can simply jump to the desired node, supported by an automatic facility for optional return to the jumping-off point. Alternatively, this capability can be blocked by a privileged user, as needed to avoid the user getting confused or distracted by the other content in the electronic textbook  5 . Blocking this capability allows the privileged users (e.g. school authorities) to crisply and unambiguously design the textbook, so that the sheer mass of material does not cause confusion or distract the student from the primary path, and so, for example, the teacher knows what the student is accessing. 
     Index: 
     The user is offered an index, comprising a complete list of available nodes and connections in the electronic textbook  5 , which can be filtered by any applicable attributes. The index can highlight categories of nodes, or categories of connections. The user is offered recommendations for paths, nodes or connections to visit, optionally supported by comments (from the author or other users), based upon the user&#39;s experiences so far. The user is offered “test your skills” questions that yield recommendations on what more may be important to learn; and alternate paths provided by the author or other users. 
     Graphical and Tabular Display: 
     This information can be displayed in a variety of ways. For example, orientation information can be displayed as a listing of connections, or as rows in a table or spreadsheet. Alternatively, orientation can be depicted graphically as a view of the nodes and connections. Similarly, an index can be offered as a table, or the indexed nodes or connections can be highlighted in a graphical view of the electronic textbook  5 , or the indexed nodes/connections can by pulled to the foreground of the view. 
     Alternatives Portrayed in Nodes: 
     The nodes in the electronic textbook  5  also offer a range of options for portraying alternatives, such as the halls of informed choice discussed above: a node can display the relevant choices at a junction; a node can welcome the newly arrived user to a path or section; a node can show a wide range of alternatives; a node can include a listing of the next nodes on the present path, or the previous nodes on the path. Of course, this information provided in the nodes can alternatively be provided in the connections. 
     Restricting Connections to Connections: 
     In an embodiment, connections to connections are not allowed. In this embodiment, connections are limited to denoting connections (including logical relationships) and texts attached to connections are meant for expanding on relationships and commenting on those connections. In this embodiment, it is unwise to attach a great deal of material to a connection because later the user might want to connect to that material and would not be able to do so. If the text in a connection gets too voluminous, it is preferable for the user to break the material apart and put the bulk of it in a node. Information can be placed anywhere, but the preferred design is for the author to place all major branch points in a kind of node generally called a “junction” that is intended to facilitate connection. Junctions include gateways, vestibules, galleries, logical “nexus points”, and non-specific junctions. This also applies to users creating overlays, as discussed in further detail below. In an alternative embodiment, where users can connect to connections, these restrictions need not apply. 
     Written, Spoken and Video Formats: 
     Although not shown in  FIG. 3 , as discussed above in an example embodiment the user is offered choices of the form of the content presented to the user, such as text, audio or video content. Each of these forms of content are presented in different nodes, or alternatively in the same node for a given information item. The author can define separate paths through each of the different offered formats, or alternatively where the different formats are presented in the same node may provide one path which captures all formats. 
     Color Blindness: 
     The electronic textbook is a natural setting in which to check for color blindness, evaluate its symptoms, and modify the color palette in diagrams and displays to best suit the user&#39;s needs. In an embodiment, the user is first asked if she or he might be color blind, or would like to check to find out. A positive response takes them to an interactive graphic that guides them through a series of simple exercises that determine the color palette they can distinguish, their “functional color palette”. If they have any form of color blindness, this palette will be comprised of only a subset of the usual range of colors. If necessary this is supplemented by various fill patterns and line patterns to fill out the requisite number of distinctions. The color-blind status and modified functional palette are stored along with the student&#39;s records. Where feasible, diagrams and exhibits provided in the electronic textbook will subsequently appear with the student&#39;s modified palette. 
     Adapting to User Preference and Performance: 
     The electronic textbook  5  of an embodiment is adaptive, and can select the form of content that the user prefers. The user can explicitly indicate to the electronic textbook  5  which form of content the user prefers. Alternatively, the electronic textbook  5  can automatically select the appropriate form of content for a given node, based on metrics such as the user&#39;s past selection of content form, or a measurement of the user&#39;s performance on test questions that are based on a given form of content presentation. Thus, if the user selected for example to receive content in written text form, and then the user performed poorly on a skill test, the electronic textbook  5  will present the user with the option to receive subsequent content in a different form, such as audio or video. Similarly, if a user selected for example video content, and then the user performed well on a skill test, then the electronic text book will deliver subsequent content in the same format (here video). 
     Procedural/Rote and Intuitive Meaning. An author can represent content in many ways: prose description, images, diagrams, outlines, procedures of thought, memorization tools, examples, exercises, games, tables. Presentations can emphasize conventional procedures and routine ways of thinking such as, grammar, vocabulary, definitions, facts and assumptions, standard problem solving methods and rote learning, and searching for information. Alternatively, the author can emphasize intuitive meaning by providing examples, reformulating narrative descriptions into solvable problems, comparing and contrasting different methods of solution, demonstrating quick shortcuts that give approximate answers, diagramming relationships, offering various kinds of games and exercises that manipulate objects on the screen, and so on. Both approaches have merits and ordinarily they should be combined, but the user can choose to emphasize some ways over others. 
     Exercises Graded for Speed as Well as Accuracy: 
     In an embodiment, in order to encourage the student user to develop practical mastery of skills and insights implicit in the material, exercises take the form of interactive games or challenges that are timed for speed as well as accuracy. Games may involve techniques like approximation, selecting appropriate tools, and appreciating underlying relationships. In general these are not “word challenges” that reward the student for correctly interpreting the meaning of the words that present the challenge. Instead the user is rewarded for understanding intuitive meaning, recognizing relationships among elements of the situation, determining which elements are significant and developing insights into how problems can be solved. Emphasizing quickness and creativity helps the student user to wake up to new approaches. Repeating exercises of similar format helps to stabilize new ways of understanding. These exercises are designed to be enjoyable as well as instructive. 
     Visibility: 
     One way to control the association of nodes  10  to each other in the electronic textbook  5  is to use the concept of visibility. Visibility refers to the subset of nodes and connections that are visible to the user at any point of time. Ordinarily the entire document is not visible. Instead the range of visibility may have been reduced in three stages: what the user can potentially see according to the prevailing arrangement, what portion of this the author or other privileged users have arranged for the user to be able to see at this present point in the path, and what the user has chosen to see from within that view. 
     Limiting Visibility to Improve Focus: 
     Limited visibility has many benefits. In a positive sense it focuses attention and adds clarity by showing what is presently most relevant. In a negative sense it sets aside what the user is not supposed to see and whatever the author or other privileged user judges to be potentially distracting, disturbing or confusing to the user. At any time the user can select a wide perspective that shows all that is presently permitted. 
     Thus, a node  10  of an example embodiment contains connections to all of the other nodes  10  in the electronic textbook  5  which satisfy a visibility parameter. Any nodes  10  which fail to satisfy the visibility parameter are not associated with each other. The visibility parameter may be defined in a variety of ways. The most straightforward visibility parameter is an author or other user&#39;s express definition that a given node, for example the node  10   b , is visible from some other node, for example the node  10   a . Creation of a path (e.g. the paths  12 ,  14 ,  16 , or the user-defined path  18  discussed in more detail below) is an example of an express definition of visibility. Creation of a logical connection such as the connections  12   c  between two nodes is a further example of an express definition of visibility. Any user following the paths  12 ,  14 ,  16  or the user-defined path  18  will see the nodes  10  they are traversing, and will also see the nodes  10  connected to these paths by the logical connections  12   c.    
     Extending Visibility to Show Options: 
     Additionally, the electronic textbook  5  can make visible nodes  10  not on the path being followed, nor associated by a defined logical connection to such nodes. For example, in the electronic textbook  5  there is no connection provided by the textbook author between nodes  10   b  and  10   f . However, as the electronic textbook  5  is used by students, suppose that it turns out that several students traverse from node  10   b  to node  10   f  on their own, without following a path left by others. These traversals are recorded, as discussed in further detail below. In an embodiment, once a sufficient number of users make a transition from one node to another, these transitions cause a connection between those two nodes to become visible to all users of the electronic textbook  5 . In this example embodiment, every node  10  has a virtual association to every other node  10  in the electronic textbook  5 . Each virtual association has a weight assigned to it, representing for example the number of users who have transitioned between the two nodes. Once that weight crosses a visibility parameter threshold, the virtual association becomes a visible connection between the nodes that all users can see. 
     Sharing Comments to Inform Choice: 
     In an embodiment, once that connection arises, some or all of the attributes and comments from the various user-defined paths are assimilated into the attributes and comments of the newly-created connection. For example, the user comments explaining why they each chose to make the transition are made visible to all users. The new connection can become part of an existing defined path, such as the paths  12 ,  14  or  16 . For example, if the majority of the users who made the transition were following the average path  12 , then the new connection is incorporated into the average path  12 . This feature allows the defined paths through the electronic textbook  5  to be updated and modified, based on the actual traversal patterns of the students using the electronic textbook  5  over time. As the students themselves discover better ways to learn the material, those discoveries are made visible to all future students. 
     Sharing Comments for the Sake of Classroom Communication: 
     By facilitating each student&#39;s search for their ideal book, the electronic textbook encourages diverse student learning experiences. It&#39;s important to promote appropriate communication that will counteract any confusions arising from diversity and preserve the cohesiveness of the class. In an embodiment, the teacher can stay in touch by regularly accessing students&#39; recorded comments. Also in an embodiment, students are able to keep in touch with one another by sharing comments, describing their experiences and offering one another encouragement. 
     Comment Walls: 
     In an embodiment, comments are available to everyone in the user group on Comment Walls. The Comment Wall is a gallery display that assembles comments from all users in the group. As explained above, any user can attach comments to any node or connection in the electronic textbook. A “user group” can be defined to include, for example, the students in a class and their teacher. Any student user who has navigated to any location can view all comments that have been attached to their present location, or that refer to a node or connection that they are considering as their next step. A user who is viewing any Comment Wall can optionally attach a fresh comment. Any student user can also view all comments within the group, regardless of topic, on a Community Comment Wall, sorted by default with most recent comment first; however, if the Community Comment Wall becomes too much of a distraction for student users, a privileged user can withdraw permission for this option. 
     Facilitating Remote Participation through Entrainment: 
     In an embodiment, the teacher traverses a path through the electronic textbook during each class and encourages the students to follow along with their own equipment. Alternatively or in addition, the teacher may project the screen image onto a larger screen for the class to view. In this circumstance, a student user who is unable to attend class in person for whatever reason and is participating from a remote location can also follow on his/her own electronic textbook while listening to an audio broadcast of the class. In this case, the remote student user&#39;s electronic textbook is entrained to the teacher&#39;s, following every step that she takes and each keystroke that she enters. (Optionally, electronic textbooks in the classroom can also be entrained in this way.) This setup permits the remote student to have a realistic experience of the class, which can be supplemented through the electronic textbook&#39;s ability to forward the student&#39;s comments to the teacher and to classmates. 
     Personalizing Visibility: 
     Additionally, as noted above, the electronic textbook  5  can make some nodes conditionally visible. For example, the electronic textbook  5  can define certain connections as visible to any users who score above (or below) a certain score on a test node, or visible only to privileged users. The electronic textbook  5  of an embodiment can also provide indications of the relative visibility of the various nodes  10 . Thus, nodes that have a high visibility score are displayed more brightly, whereas nodes with a low visibility score may be displayed in a grayed-out or faded style, or using some other way of signaling that the node has a lower visibility score. 
     Adaptive Emphasis of Logical Connections: 
     In a preferred embodiment, these spontaneously-generated connections are only allowed to arise where the author has anticipated the possibility of a spontaneous connection due to a logical connection identified by the author. A textbook author identifies the likely sources for the more probable connections, such as regional or cultural knowledge, the same topic at different levels of performance, the same topic in procedural and intuitive ways, the same problem solved differently, or reference to glossary or definition. Where a possible linkage can be anticipated and understood by the author, the author permits this connection to become visible if enough users traverse it. For instance, if more students go to advanced and/or remedial material or go from procedural material to intuitive material and examples; or go from one approach to solving a problem or another, or to the glossary or to a definition, then the electronic textbook can benefit the student by promoting the visibility of those paths. Also whenever the author offers a junction, and especially when it is a major one, it is a natural idea to display frequency of choices made by users in a useful way. When the link is by unstructured association not anticipated by the author, by contrast, allowing spontaneous connections might disorder the experience of the textbook. In alternative embodiments, however, where users are given more freedom to form their own associations, spontaneous connections are permitted between any nodes, as discussed above. 
     Arranging Tie-Ins for Supplementary Material: 
     Turning to  FIG. 5 , the author can also incorporate tie-ins in the electronic textbook  5 . For example, at node  10   g , the author inserts a tie-in, to indicate an appropriate location for others to insert additional content into the electronic textbook  5 . This additional content could be content tailored to a given user community, such as a school district, a school, or an individual teacher&#39;s classroom. For example, for a textbook discussing the history of the Spanish missions in California, the author includes a tie-in indicating that the node  10   g  is an appropriate place for a school district to insert additional content, such as the L-nodes and connections  14   c  shown in  FIG. 5 , about the particular Spanish mission (e.g. Mission San Juan Capistrano) located nearest the district. In the example of  FIG. 5 , this tie-in is located on the advanced path  14 , but of course these tie-ins can be located on any or all of the paths  12 ,  14 ,  16  in the electronic textbook  5 . 
     Interlinking Electronic Textbooks: 
     These tie-ins can even incorporate one or more entire additional electronic textbooks created according to embodiments of the invention. This allows for an entire series of electronic textbooks to be seamlessly melded together into a single electronic textbook  5 , covering an entire multi-year curriculum for a given subject matter. Thus, a school could present the entire K-12 mathematics curriculum to its students as a single electronic textbook  5 . This would allow the students to proceed at their own pace across multiple years of education, picking up where they left off the prior year in each instance. Through use of skills tests as discussed above, such an electronic textbook  5  captures any loss of skills over a break in the student&#39;s education, such as over a summer break. The electronic textbook  5  can then direct the student to the appropriate remedial instruction, by switching the student to the appropriate path through the electronic textbook  5 . 
     Paths, Comments and Additions: 
     Once the author has completed preparation of the electronic textbook  5 , the electronic textbook  5  is made available to other users. These users can include the ultimate end users, such as the students who will use the textbook  5  as a learning tool. Additionally, these users can include privileged users, such as a state, county or local school board, a school district, an instructor, or a school or university. In rare cases, legal issues associated with aspects of the book may bring in the judicial system as well. Each user to whom the textbook  5  is made available has the ability to navigate the textbook  5  and to add comments and additional content to the textbook  5 . A privileged user, such as an instructor, may use this facility to tailor the textbook  5  to regional, local, and even personal needs. Beyond this, each individual user has the capability to add material in the form of personal comments and notes and also to share material with other users. The textbook  5  becomes a personalized textbook for each user. Alternatively, as discussed further below, with reference to  FIGS. 7 and 9 , the user&#39;s comments may be saved separately as an overlay  41 . 
     Recording User Choices, Comments and Interactions: 
     Turning to  FIG. 6 , a user begins using the textbook  5  at node  10   a , where the user answers the initial test questions. In this example, the user&#39;s answers indicate that the user is best suited to begin on the average path  12 . The user&#39;s path through the textbook  5  is indicated by the reference  18 . When the user interacts with node  10   a , the user is given the opportunity to provide comments regarding his/her decision to visit this node. Those comments are stored as part of the user&#39;s path  18  through the electronic textbook  5 . The user&#39;s interaction with the node  10   a  is also stored as part of the user&#39;s path  18 . Thus, the information the user accessed is tracked, including the responses the user gave to the test questions. This information is made available for use by the privileged users, or by other users of the electronic textbook  5 . The scope of access of this information may be configured, either by the author, by privileged users, or by the user using the textbook  5 . For example, access to the information could be restricted just to the user, or just to the user and designated privileged users such as the instructor for the class or the user&#39;s parents, or could be made available to all of the students in the same class. 
     Templates for Comments: 
     The user is optionally permitted to select any path leaving node  10   a . Alternatively, the user is guided to the average path  12 , or even required to follow the average path  12 . The configuration of node  10   a , including indications of which other nodes  10  the user is allowed to traverse to, may be done by either the author, or by one of the privileged users identified above. In this example, the user then navigates to node  10   b , along the average path  12 . Again, the user is given the opportunity to provide comments regarding her/his decision to traverse the connection between the nodes  10   a  and  10   b , including for example reasons why the user chose not to follow the other connections out of node  10   a . In an embodiment, these comments are free-form reactions or personal notes, with most of the usable feedback for the author coming from the frequencies with which paths are chosen. Alternatively or additionally, the comments may be collecting using standardized templates for data entry that would result in comments friendly to generic treatment by search engines to create population statistics (e.g. the template could be formatted as a form to fill out). For example, in a shared environment such as the overlays discussed below, with reference to  FIGS. 7 &amp; 9 , the standardized template could be developed by a search provider and made available to the users creating the overlays. In the textbooks for use in the earlier grades, by contrast, this kind of structured comment sharing may be distracting to the student. At higher grade levels, where students benefit more from shared learning experiences, standardized templates can be provided. Alternatively, as discussed further below, with reference to  FIGS. 7 and 9 , the user&#39;s path  18  and associated comments may be saved separately as an overlay  41 . 
     Upon arriving at node  10   b , the user processes the content stored in node  10   b . For example, the user reads the text for node  10   b , or views a video or image, or listens to an audio presentation regarding the content of node  10   b . As discussed above, the user optionally chooses a format for the content of node  10   b  that the user desires to receive, such as text, audio, image or video format for the information in node  10   b . Node  10   b  contains several connections to other nodes  10  in the electronic textbook  5 . There is a sequential connection  12  from node  10   b  to node  10   k , along the average path  12 . There is also a pair of connections  12   b  from the node  10   b  to the node  10   c  and back. Finally, there are two logical connections  12   c , one from node  10   b  to node  10   j  on the advanced path  14 , and a second from node  10   b  to node  10   i  on the remedial path  16 . 
     Reviewing Comments and Personalized Access: 
     In an example embodiment, the user is presented with all of these connections, and allowed to choose which connection she/he wishes to follow. The user may review any comments left by the author, privileged users, or other users who previously travelled along any of those connections, to aid the user in deciding which connection to take. Alternatively, some of the connections from node  10   b  are obscured, such that the user cannot see them. These obscured connections may be made available only to privileged users. The privileged users are permitted to traverse these connections, and make the connections available to other users. Alternatively, some of the connections are made available only to users who first complete a task such as reading a text, viewing an image or video, listening to an audio recording, or responding to a test question in the node  10   b.    
     In the example of  FIG. 6 , the user, upon visiting node  10   b , decides to investigate the content of node  10   i  on the remedial path  16 . Node  10   i  is identified in node  10   b  as a logically-related node  10 . For example, the user decides that he would like additional information about the subject matter of node  10   b , and identifies node  10   i  as a helpful source of additional information. In one example, the user reviews comments left by other users who visited node  10   b , and decides based on those comments that node  10   i  is likely to contain additional useful content for the user to review, in order to learn the subject matter of the electronic textbook  5 . Alternatively, the user is presented with a preview of the content at node  10   i , or simply with a title indicating the content located at node  10   i . The user is given the opportunity to record comments as to why the user chose to visit the logically-related node  10   i , rather than continuing on the path  12 . These comments are saved into a database associated with the electronic textbook  5 . Alternatively, as discussed further below, with reference to  FIGS. 7 and 9 , the user&#39;s path  18  and associated comments may be saved separately as an overlay  41 . Thus the user is, in an embodiment, permitted to change paths even in nodes which do not include test questions as discussed above. 
     User-Contributed Content: 
     The user visits node  10   i , reviews and processes the content located in that node, and leaves any further desired comments. In this example, the user decides that the content at node  10   i  should be augmented. For example, the user in reviewing the content at the node  10   i  realizes that the content is related to other content the user is aware of, which is not in the electronic textbook  5 . Alternatively, the user concludes that the content at node  10   i  is incomplete, or difficult to follow, or out of date, or overly simplified. Thus, the user determines that his own educational experience, or the educational experiences of other users, would be enhanced by providing the additional content. 
     In one embodiment, the user is not permitted to revise the content stored in node  10   i , for example because the user is not the author of the electronic textbook  5 . The user is, however, permitted to add nodes  10  to the electronic textbook  5 , to personalize the textbook  5 . The user thus adds the U-node  10   j  to the electronic textbook  5 , containing the additional content identified by the user. If the user is permitted to modify the content of the node  10   i , for example if the user is a privileged user or the author of the electronic textbook  5 , then the user optionally updates the node  10   i  with the updated content, instead of creating a new node  10   j  with that content. 
     In an embodiment, adding the node  10   j  to the electronic textbook  5  occurs automatically, as a result of the user visiting the node  10   j , for example by navigating to it. The electronic textbook  5  automatically records the user&#39;s connection to the node  10   j  by capturing that connection when the user uses it to navigate to the node  10   j . The electronic textbook  5  also captures the content of the node  10   j , and incorporates it into the textbook  5 , for example by storing the content in a database containing the textbook. Alternatively, the electronic textbook records only the connections to the content and does not record the content itself. Alternatively, the user expressly specifies one or more connections between the new node  10   j  and other nodes  10  in the electronic textbook  5 . Alternatively, as discussed further below, with reference to  FIGS. 7 and 9 , the node  10   j  and associated comments may be saved separately as an overlay  41 . 
     The user then adds any desired comments, such as an explanation of why the user visited the new content, why the user wanted to add the new content to the textbook  5 , or the like. When the user leaves the node  10   j , and returns back to the previously existing nodes  10  in the electronic textbook  5 , the return path is also automatically captured and stored in the electronic textbook  5 . In the example of  FIG. 6 , the user goes back to the node  10   i  after visiting the new node  10   j . Alternatively, the user may be presented with other nodes  10  to visit instead of the node  10   i . For example, the user could be presented with a list of all nodes  10  that are visible from the node  10   i  that the user most recently had visited, thus giving the user more flexibility in deciding where to go next in his educational journey of exploration. 
     User-Contributed Connections: 
     In the example above, the added content was not already in the electronic textbook  5 . In another alternative example, the user realizes that the content at the node  10   i  is related to other content that is located in the electronic textbook  5 . In this example, the user simply adds another connection to that content, for example by navigating to that content, and then provides any desired comments indicating for example why the user made the connection. 
     Accessing a Glossary: 
     In a related context, the electronic textbook  5  can include a glossary (not shown), which provides definitions of key terms used in the electronic textbook. The user, wishing to understand the meaning of a term, can click on the term and be taken to the glossary definition. This glossary definition is stored in a node  10  of the electronic textbook  5 . Thus, the user&#39;s traversal to the node  10  of the glossary, and back, is stored as part of the user&#39;s path  18  through the electronic textbook  5 . 
     Bypassing Test-your-Skills: 
     From the node  10   i , the user continues building the path  18  through the nodes  10 . The user, having chosen to switch from the average path  12  to the remedial path  16 , continues on the remedial path  16  to the node  10   f , for additional remedial instruction. After reviewing and processing the content of node  10   f , the user is presented with another option, to either continue on the remedial path  16  to the next node  10  on that path, or alternatively to proceed on the path  16   a  to the test node  10   e . In the example embodiment shown in  FIG. 6 , the user is further given the opportunity to bypass the test node  10   e  and proceed directly back to the average path  12 . 
     Users are permitted to bypass test nodes for a variety of reasons. For example, where the user starts on a given path (such as the average path  12 ) and then chooses to deviate from that path, the user is permitted to return to the path originally selected at any time. Alternatively, the user may be permitted to skip over test nodes as desired, even if the user is not returning to a path previously followed. Alternatively, the user may be permitted to navigate to any node that is visible to the user, as discussed above, even if doing so would bypass a test node. 
     Once the user navigates to the node  10   k , the user then follows the average path  12  through the remaining nodes  10  in the electronic textbook  5 , until the user reaches the end of the average path  12 . Along the way, the user is permitted to provide comments for each node  10  visited, and for each step along her/his path  18 . These comments can include the user&#39;s reactions to the content of the nodes  10 , the user&#39;s reasons for selecting the steps of the path  18 , or other comments as desired by the user. 
     Revisiting the Path Taken: 
     At any point during the user&#39;s traversal of the path  18 , the user optionally may revisit his/her path  18 , provide additional comments about previously visited nodes  10 , edit or remove previously recorded comments, and edit or remove any of the connections on the path  18 , or any nodes  10  or other content added by the user. Alternatively, some or all of the user&#39;s ability to modify or remove content may be constrained. For example, it may be helpful for a teacher to understand the complete path a user travelled through the electronic textbook  5 , even though the user wanted to conceal an aspect of the path. This would give the teacher a better understanding of the user&#39;s actual educational journey. 
     Privacy: 
     As the user is traversing the nodes  10  of the electronic textbook  5 , and creating the path  18 , this path is saved by the electronic textbook  5 , along with the user&#39;s comments. Alternatively, as discussed further below, with reference to  FIGS. 7 and 9 , the user&#39;s path  18  and associated comments may be saved separately as an overlay  41 . The path  18  and the user&#39;s comments may be secured as private to the user. Alternatively, the path  18  and the users&#39; comments are provided to other users of the electronic textbook  5 . For example, the path and comments are provided to the user&#39;s teacher, so the teacher can monitor the user&#39;s progress through the electronic textbook  5  and provide additional instruction where needed. Similarly, particularly where the user is a primary or secondary school student, the user&#39;s path may be provided to the user&#39;s parents, so that the parents can monitor the user&#39;s progress and provide assistance where needed. 
     Advantages of the Electronic Textbook: Each User&#39;s Ideal Book: 
     The electronic textbook  5  of an embodiment provides a number of advantages over conventional textbooks. Student users are diverse. Boys and girls are distinct and have different learning styles. Students vary in ability, preparation, experience and relative facility with different forms of learning, such as text-based (verbal) or image-based (visual) learning styles. Students&#39; experiences vary by locality, family environment and language at home. An author can use the electronic textbook  5  to deliver an ideal book to each of a wide variety of students, with each student exploring and discovering the book that best fits him or her. The electronic textbook  5  contains enough diverse material to provide a path through the electronic textbook  5  that reflects a book tailored to each student&#39;s educational needs and preferred way of receiving educational content. The electronic textbook  5  provides content in the nodes  10  which informs the student&#39;s choices well enough to permit the students to find their own preferred path (i.e. book) amongst all of the other possible paths contained within the electronic textbook  5 . This variety allows the author to create a better book for the students than any traditional linear textbook, because the author can offer the students choices and can help the students discover the instructional material that best reaches each student. 
     Advantages of Tie-In Points: 
     As discussed above, the electronic textbook  5  need not supply the entire universe of material on a given subject matter, for all students. Instead, the electronic textbook  5  provides tie-in points where other privileged users such as school districts can supplement the electronic textbook  5  with local material. This is an advantage of the electronic textbook  5  of an embodiment; it is arrangeable by multiple users. Furthermore, privileged users can extend the tie-ins by defining additional tie-in points that allow other privileged users to further tailor the educational content. For example, the state&#39;s board of education can define tie-in points where a local school district may tailor content. The school district can define tie-in points where a school may tailor content. The school can define tie-in points where a given teacher may tailor content. The teacher can define tie-in points where students and family members may tailor content. Thus, each level of authority can provide as much or as little flexibility as desired for subordinate users to supplement the electronic textbook  5 . 
     Advantages of Paths at Average, Advanced, and Remedial Levels: 
     As discussed above, the electronic textbook  5  has multiple pre-defined paths  12 ,  14 ,  16  and also additional user-defined paths such as the path  18 . This feature allows the electronic textbook  5  to satisfy the needs of a diverse student population. For example, the primary path through an electronic textbook  5  is the average path  12 , which is designed by the author to be most suitable for average students. Along the way, at suitable points as discussed above (e.g. nodes  10   c  or  10   k  of  FIG. 3 ), advanced topics are offered as optional choices to the student. As a result, advanced and interested students will learn more and learn more actively, by being engaged in their own education. They naturally select the advanced options, find them interesting, and settle onto an advanced path while also covering the average material. The advanced path  14  offers even more advanced material, and is suitable for higher level courses. 
     Remedial support can be offered in a friendly way, promising clarification and more extensive examples. Thus, the nodes  10  on the remedial path  16  contain additional clarifying and explanatory content. These nodes  10  can also include additional connections to additional nodes which supply even more examples or clarifying content. These clarifying nodes can be made available to the other paths  12 ,  14  as well. One example of this is the node  10   c  above, which provides clarifying content to users on both the average and the advanced paths ( 12 ,  14 ). By providing the user with multiple interconnecting paths through the electronic textbook  5 , the user is empowered to tailor the content to the user&#39;s comfort level, by changing paths or selecting optional nodes  10  as the user&#39;s comprehension of the material fluctuates through the user&#39;s traversal of the electronic textbook  5 . 
     The remedial path  16  is also available as an initial path through the electronic textbook  5 . Users that are identified as needing simplified materials, such as those with learning difficulties, or those with low scores on an initial test (e.g. the test in node  10   a  above) will follow the remedial path  16 . Users on this path will ordinarily see simpler content, exercises and test questions. However, these users are also presented with richer optional content, which comprise examples on the average path  12 . Those examples may permit the remedial user to continue navigation along the average path  12 , or alternatively may restrict the remedial user to returning back to the remedial path  16  after the user has processed the richer optional content. 
     Self-Correcting Paths: Fixed Thresholds: 
     Another advantage of the textbook  5  of an embodiment is that the paths  12 ,  14 ,  16  are self-correcting. For example, assume that the author creates an electronic textbook  5  with an average path  12  that turns out to be too difficult for the average student. As the students use the electronic textbook  5 , they will naturally drop down to the remedial path  14 . Over time, the number of users of the electronic textbook  5  using the remedial path  14  will increase. This use pattern can be detected by the electronic textbook  5 , and the electronic textbook  5  can adjust the default paths accordingly. For example, the electronic textbook  5  can examine the usage volumes for each node, or connection between nodes, and assign the path with the most traffic as the average path  12 . Similarly, the electronic textbook  5  can adjust the paths based on other metrics, such as average test scores for users taking a test at any given node, or combination of nodes. Thus, the path favored by users who score highly on the test nodes can be designated the advanced path  14 , whereas the path favored by users who score poorly on the test nodes can be designated the remedial path  16 . 
     Self-Correcting Paths: Adaptive Thresholds: 
     In another embodiment, the threshold test scores are self-correcting. Observing the subsequent performance of users juxtaposed with their initial test scores, if for example, the lower threshold for the average path  12  was 80, but it was discovered that students who scored between 70 and 80 on the test usually transitioned quickly to the average path  12 , then the threshold could be lowered to 70. 
     Elevating Students to Advanced Material: 
     As discussed above, the electronic textbook  5  of an embodiment includes nodes  10  which test the user&#39;s comprehension of the material. These tests provide a useful feedback to a user of the electronic textbook  5 . Sometimes, a user will not realize that they do not understand a particular aspect of the subject matter being taught. The test nodes allow the electronic textbook  5  to guide these users to the support they need. The test nodes also allow the electronic textbook  5  to elevate more advanced users to the more challenging material, to ensure that the advanced users retain their interest in the material, and are challenged by the material. 
     Refocusing Students on Remedial Material: 
     In an embodiment, the tests are required for users who are having difficulties with the material. Additionally, the electronic textbook  5  can provide additional nodes  10  which are also required for the user to review and process, if the user is having difficulties. The electronic textbook  5  can, for such nodes, disallow or disable the user&#39;s ability to travel to other nodes in the electronic textbook  5 , until such point as the user has demonstrated mastery of the subject matter the user was having difficulty with. For example, the user may be required to review the additional nodes  10  and then answer further test questions, before the user is permitted to navigate out of the series of remedial nodes  10 . If the user continues to have difficulties, and makes further mistakes in the tests, then the user can be transitioned to still further nodes  10 , which include special content directed to helping the student figure out why the student made a particular mistake. Once the electronic textbook  5  identifies the reason for a user&#39;s mistake, the electronic textbook  5  then takes the user to remedial content tailored to the reasons for the user&#39;s mistake. This content is followed up with another test exercise, to confirm that the user has learned the material. 
     Remedial Resources for All Students: 
     These same content nodes  10  and test nodes  10  are also made available to users who are not having difficulties, should those users wish to navigate to these nodes for additional information. However, such users are not required to review these nodes  10 , and are permitted to navigate away from these nodes  10  at any time once they begin reviewing them. This is one example of how the electronic textbook  5  of an embodiment presents content that is tailored, or fine-tuned, as the user reads the electronic textbook  5 . 
     Adapting the Path to Performance: 
     As a user&#39;s performance on the exercises or tests in the electronic textbook  5  varies over the course of the user&#39;s navigation through the electronic textbook  5 , the level of challenge of the tests and exercises can be dynamically adjusted. Thus, a user can begin navigating through the electronic textbook  5  as a remedial user, following the remedial path  16 , and end up as an average user following the average path  12 , without ever being expressly told that the user has changed paths to a more challenging path. Thus, a user with anxieties about his or her learning ability is not scared off from the content by concerns that the content is not appropriate for the user (i.e. it is “too hard” or “only for the smart kids”). Instead, the user simply experiences a default or recommended path through the content as it unfolds. 
     In an embodiment, as a user progresses through the content, completes exercises, takes tests, and makes choices to view more or less advanced material, the electronic textbook  5  adjusts the recommended path presented to the user, to factor in these dynamic variables. Thus, if a user performs well on exercises and tests, and is consistently selecting advanced optional content to view, the electronic textbook  5  can recommend more advanced content for the user to review. This selection can take the form of an express primary path switch, to elevate the user to the advanced path  14 , for example. Alternatively, this selection can take the form of making visible more nodes  10  on the advanced path  14 , or increasing the visibility level or priority listing of nodes on the advanced path  14 , using the visibility metrics discussed above. Similarly, if a user performs poorly on exercises and tests, and is consistently selecting remedial optional content to view, the electronic textbook  5  can recommend more remedial content for the user to review. 
     Choices Regarding Modes of Instruction: 
     The electronic textbook  5  also offers different forms of instruction, as discussed above. This instruction can emphasize words and verbal logic, or it can emphasize images and kinesthetic/visual experiences. The user&#39;s choices in selecting content to review will disclose their preferred forms of learning. The electronic textbook  5  records these selections, and uses them to make recommendations to the user as the user visits further nodes  10  in the electronic textbook  5 . The electronic textbook  5  is thus able to help users better comprehend the instructional material, by presenting material in a format tailored to each user. 
     Analyzing and Adapting to Performance and Preference: 
     The patterns identified by the electronic textbook  5 , including the performance patterns and content format patterns discussed above, are used by the electronic textbook  5  to provide further recommendations to the user. For example, when a user completes a module, a given electronic textbook, or a grade level, the patterns are retained and re-used to provide recommendations for the next module, electronic textbook or grade level. Thus, in an embodiment the initial test questions presented in node  10   a  need only be presented for the very first interaction a user has with the subject matter of the electronic textbook. All subsequent interactions with that same subject matter, for example as the user progresses through the different grade levels (K-12) in a subject such as mathematics, are governed by the user&#39;s prior patterns as recorded and retained by the electronic textbook  5 . Thus, a user who completes a first grade electronic textbook of an embodiment of the invention on the advanced path will automatically be started on the advanced path of the second grade version of the electronic textbook. Similarly, a user who has demonstrated a preference for visual content will be offered visual content in the second grade electronic textbook as well. 
     Multi-Media Textbook: 
     The electronic textbook  5  of an embodiment is a multi-media textbook. Thus, an electronic textbook  5  can provide both visual and auditory materials, as well as, with use of appropriate sensors such as a haptic feedback device, materials that stimulate touch or other human senses. Auditory recordings can be the primary format for delivering the educational content. Thus an electronic textbook  5  can deliver rich educational content to users who cannot process visual materials well, for example because the user is illiterate or vision-impaired. The auditory electronic textbook  5  can also present educational content that is historically audio-based, such as oral histories or stories. Alternatively, the auditory content can be supplemental or optional, as discussed above. One particularly useful way to incorporate auditory content is to provide a tie-in point for a teacher to create a new node  10  (or update an existing node  10 ) with a recording of the teacher&#39;s words of explanation or encouragement for their own students. This provides the user (who may be a young child in some embodiments) with a familiar and supportive teacher&#39;s voice. This would be a heartening experience for the user during the user&#39;s studies or homework sessions. Similarly, a family member could record words of encouragement that would appear periodically, such as at the end of a test or a module, to further motivate the user to succeed. Of course, a video recording could be included in addition to an audio recording. 
     Guides for Teaching: 
     The ability for an electronic textbook  5  of an embodiment to offer a variety of paths through the same content also helps guide other users of the electronic textbook  5 . For example, where the user is a juvenile student, the user&#39;s parents and other family members will often want to help the student understand the material. The parents may have a good understanding of the subject matter the student is learning, but they may lack the ability to explain it clearly or teach through simple examples. The electronic textbook  5  of an embodiment provides a parent path through the material, which contains explanations of the material tailored to facilitate a parent&#39;s efforts to explain the material to his or her child. This parent path can be a path through additional or separate nodes  10 , or it can be an overlay of comments onto the path (e.g. paths  12 ,  14 ,  16 ) that the student user is following. The comments can come from another user, such as the child&#39;s teacher, the author of the electronic textbook  5 , or an author of a study guide which accompanies the electronic textbook  5 . The comments for the parent path can be different from the comments for the student path, even for the same node  10 . This is another example of how the content of a node  10  is tailored or presented in a context-sensitive manner, based on the path the particular user followed to arrive at the particular node  10 . The parent user following the parent path can, of course, navigate to the student&#39;s path ( 12 ,  14  or  16 ) as needed for the parent to understand the material sufficiently to assist the student user. This example of two parallel paths for the student and the parent illustrates the use of structured connections (a subtype of logical connections), which can be usefully offered in a special way (for example side-by-side displays in the textbook reader  21  of  FIG. 4 .) Similarly, an author of the textbook  5  can include a path through the nodes  10  of the textbook  5 , or an overlay  41  as discussed in further detail below, which contains comments intended for the teacher. This path provides a teaching guide, incorporated in or associated with the electronic textbook  5 . 
     A Learning Resource for Teachers: 
     An electronic textbook  5  according to embodiments of the invention, as discussed above, is also a useful learning tool for the classroom teacher. The electronic textbook  5  presents a variety of different learning paths through the subject matter. The electronic textbook  5  further provides a variety of different learning formats, and caters to diverse learning skills. A teacher following these learning paths and absorbing these learning formats and skills will use the electronic textbook  5  as an educational training tool. The teacher, by studying the electronic textbook  5  and following the diverse paths through the electronic textbook  5 , learns how to give personalized instruction to each individual student based on the student&#39;s identified individual needs. 
     Extending Beyond a Single Course: 
     Because the electronic textbook  5  of an embodiment can be modified or extended, the electronic textbook  5  is not limited to a particular subject or a particular grade level, as is the case with traditional textbooks. An author can create a single electronic textbook  5  containing an entire course of study for a particular broad subject matter, for example mathematics, beginning with the very basic concepts of kindergarten mathematics (e.g. basic counting and addition) and concluding with advanced mathematical concepts suitable for high-performing 12th grade students (e.g. calculus or differential equations). The same electronic textbook  5  is then used to teach this subject to the users throughout their careers as K-12 students. This allows each student to find his or her own skill level with the material, year after year. Each student is able to move at his or her own pace through the material. Each student is able to review the material he or she learned in prior years, even where there have been significant breaks in the educational progress of the student, for example a break between grade levels such as a summer vacation between two primary grade levels. The students are able to maintain a continuous course of study across multiple grade levels, because they use the same electronic textbook  5 , tailored to the student&#39;s individual learning style. 
     Intuitive Meaning as Well as Rules and Procedures: 
     In one example embodiment of an electronic textbook  5 , pertaining to mathematics texts, existing math textbooks generally focus on teaching rules and procedures rather than fostering intuitive knowledge of the meaning and usefulness of the material. The electronic textbook  5  of an embodiment offers multiple different instructional paths through the nodes  10  of the mathematics electronic textbook  5 . These paths include a first path which supplies the conventional rules and procedures for learning mathematics. These paths also include an alternative, intuitively meaningful second path that dovetails with the conventional procedural instruction on the first path. These two paths intersect at particular nodes  10  which teach key concepts necessary for all students to learn the material (e.g. 2+2=4). However, the intuitively meaningful second path provides additional or alternative nodes  10 , which rely on teaching by experience rather than teaching rules and procedures. This second path allows the student to experience for her/himself how counting and calculating reveal useful qualities of our world, and how numbers can be used for calculation and communication. 
     The alternate second path can be optional, with the expectation that many teachers will present it systematically as supporting material. It can also serve as the sole acceptable teaching method for certain students who do not do well with the procedural approach. The student may be impatient with a rule-based unintuitive mindset, as the great genius Albert Einstein was in his school years, or may be forced to rely primarily on intuition because of a disability such as dyslexia or anxiety about math. 
     Reporting Progress when Appropriate: 
     Electronic textbooks according to embodiments of the invention are administered to allow other users to observe and address the student users&#39; progress. The electronic textbook  5  can, in an embodiment, be distributed to individual users, for example by being downloaded to a given user&#39;s computer, tablet or other suitable electronic device. The electronic textbook  5  may periodically report data back to other users such as the teacher, or it may alternately preserve the user&#39;s information strictly private. This permits the user to exercise more control over access to the user&#39;s stored information, such as the user&#39;s comments, test results, progress through the electronic textbook  5 , etc. 
     Alternatively and preferably, the electronic textbook  5  of an embodiment is stored in a centrally-accessible location, available to an entire community of users. For example, the electronic textbook  5  is stored on and made available from a computer connected to a network such as the Internet. In this embodiment, the teacher can access each student user&#39;s engagement with the electronic textbook  5 . The student user&#39;s path through the electronic textbook  5  and the choices that the student user made are important indications of how well the student user is learning the educational content, as well as indicating which formats for the material (e.g. textual, audio, video) are most beneficial to the student user. Making these records available to the teacher provides a reliable feedback mechanism to the teacher. Providing the electronic textbook  5  at a centrally-accessible location is also useful in connecting widely-separated users, such as home-schooled students, or students located in geographically remote regions. 
     Information Transmitted to the Teacher: 
     Thus, in an embodiment, the teacher can access the student&#39;s path through the various nodes  10 . The teacher can observe any other metrics stored by the electronic textbook  5 , such as the time each user spent visiting each node  10 , the comments the user left as he or she traversed the electronic textbook  5 , or the user&#39;s performance on exercises or tests. Furthermore, other diagnostic calculated data can be reviewed, such as indications of whether the user is classified as remedial, average or advanced, whether the user is following a procedure-based path or an instruction path based on intuitive understanding, or whether the user is selecting textual, audio or video formats for the instructional content. The electronic textbook  5  calculates this information as part of recording the student&#39;s path through the material, and to support the various recommendations discussed above. By storing the electronic textbook  5  in an accessible location this information can be opened up to other users in the community, such as teachers, parents or administrators. 
     “Wrappers”: 
     For example, in an embodiment, the student user systematically prepares focused comments known as “wrappers” for personal benefit that are also made available to the teacher. For instance, these can be prepared after each exercise, test your skills exam and after the completion of each chapter of the electronic textbook. Wrappers can also be submitted at any point where the student accomplishes an expressed goal or turns away from a goal. The wrapper is a form of reflection on personal involvement that should be prepared soon after completing a project or receiving feedback on performance, A wrapper can address such aspects as prior study strategies, experiences during the event, analysis of mistakes, and intent to modify study strategies. Submitting the wrapper to the teacher, parent or mentor creates an opportunity to receive feedback, support and useful advice. 
     Alternatively, a middle ground may be implemented, where the electronic textbook  5  is stored in a centrally-accessible location, and the diagnostic data on the user&#39;s traversal through the electronic textbook  5  is also stored in a centrally-accessible location, but where the user&#39;s comments and additional nodes  10  added to the electronic textbook  5  are stored locally as an overlay, such as the overlay  41  described in further detail below with reference to  FIGS. 6 &amp; 7 . 
     Management by Multiple Levels of Administration: 
     Additionally, as discussed above the electronic textbook  5  of an embodiment is managed by multiple levels of administration, including for example a state board of education, a local school board, a school, an administrator such as a special resources or special needs coordinator for special needs students, and an individual teacher. Each of these entities is allowed to provide input on matters such as approval of content, approval of instructional formats, approval of content format (e.g. text, audio or video), addition of tailored instructional content, addition of comments, addition of alternative content formats or instructional formats, etc. Furthermore, in an embodiment there is a hierarchy of such entities, such that a superior level entity is allowed to make decisions about which features of the textbook  5 , such as particular nodes  10  or paths  12 ,  14 ,  16  are required to be included in the textbook  5 , or optionally may be included in the textbook  5 , or are prohibited from the textbook  5 . Inferior entities are then allowed the flexibility to further modify the available content, within the parameters established by the superior entity. 
     Thus, for example, a state board of education could determine that a particular set of nodes  10  and paths  12 ,  14 ,  16  was required in all textbooks on a given subject within the state. The local school board could then determine that additional nodes  10  and connections  7  in the paths  12 ,  14 ,  16  were required in all mathematics textbooks used in that district. The local school board could further determine that individual schools and teachers were permitted to add tailored content to certain nodes  10 , but were not permitted to add tailored content to other nodes  10  for which the school board wanted to enforce a common core curriculum (e.g. for nodes  10  directed to preparation for a district-wide test, for which it was considered important that all students be given the same preparation). 
     This regulatory structure is provided, in an embodiment, by allowing each administering entity to arrange properties for each node  10  or connection  7  in the paths  12 ,  14 ,  16  in the electronic textbook  5 . These properties include, for example, whether the node or connection is mandatory, optional, or prohibited, whether modification of the node or connection is permitted, whether additional nodes or connections can be added to the node, whether comments can be added to the node or connection, whether content formats can be added to or removed from the node, whether the node or connection is visible, or can be made visible as discussed above, etc. 
     Separable User Overlays: 
     In example embodiments discussed above, the electronic textbooks included both the nodes  10  and the connections (e.g. paths  12 ,  14 ,  16 ) between the nodes  10 , and the paths (e.g. path  18 ) followed by users navigating the nodes  10 . In an alternative embodiment, the connections and/or the paths can be maintained separately, as an overlay to the electronic textbook  5 , such as the overlay  41  discussed in further detail below with references to  FIGS. 6 &amp; 7 . This allows users to make their own private overlays which the user can store securely and separately from the underlying electronic textbook  5 . The user also can distribute the overlay separately from the textbook  5 . This also allows authors to construct different electronic textbooks which each rely on some or all of the same underlying set of nodes  10  for the underlying content. For example, an author can construct a remedial textbook, an average textbook, and an advanced textbook all relying on the same set of nodes  10  as shown in  FIG. 1 . The remedial textbook includes the nodes  10  and the remedial path  16 . The average textbook includes the nodes  10  and the average path  12 . The advanced textbook includes the nodes  10  and the advanced path  14 . Alternatively, the author can simply distribute the electronic textbook including just the nodes  10  to all users, and then separately distribute the appropriate path  12 ,  14 ,  16  as an overlay to the electronic textbook  5 , tailored to each user&#39;s particular needs. 
     Overlays can be Shared: 
     The overlays of an embodiment are also useful for the users to make comments on the electronic textbook  5  as discussed above, including for example taking notes to assist the user in reviewing the material. As discussed above, comments can be appended to the nodes  10  or connections  7  or the paths  12 ,  14 ,  16 ,  18 . In an embodiment using overlays, the comments are provided as a separate overlay to the electronic textbook  5 . The comments then can be separately stored and distributed to other users, without requiring distribution of the electronic textbook  5  itself. The comments can be juxtaposed to the nodes, connections or paths that they relate to, by any user with access to both the comments and the underlying electronic textbook  5 . The user can navigate through the comments and the underlying electronic textbook  5  at the same time. Additionally, the user can review the comments independently of the electronic textbook  5 , as desired. In an embodiment, the user can review the comments overlay, and then navigate to the underlying node, connection or path to which the comment applies, for example by clicking on the comment. 
     Overlays as Study Guides: 
     These comments can also be distributed to other users as a study guide. A user, such as a particular student, or a teacher, or even the author of the electronic textbook  5 , can create a separate overlay containing comments about the instructional material in the electronic textbook  5 . The overlay is tied to the nodes, connections and paths in the electronic textbook  5  (or in other overlays for the electronic textbook  5 ). These comments are then provided to other users as a stand-alone study guide for the electronic textbook  5 . 
     Overlays as Development Tools: 
     These overlays are also useful to authors, preparing to write the electronic textbook  5 . The author compiles a collection of instructional material which will form the nodes of the electronic textbook  5 . The author then begins creating connections between the various pieces of instructional material in the collection, to develop dependencies between these pieces. These dependencies will ultimately inform the author&#39;s decisions as to which connections or paths to build through the instructional material of the completed electronic textbook  5 . Since the dependencies created by the connections are, in this embodiment, provided as a separate overlay, the author can model many alternative dependencies, and can add or remove dependencies without disturbing the underlying instructional material or the other overlays. 
     Applications in Higher Education: 
     In embodiments of the invention, electronic textbooks for college and graduate studies can be lower-cost alternatives to printed textbooks that allow for regular updates at reasonable cost. When compared to traditional printed textbooks, electronic textbooks can present complex knowledge in depth much more effectively, link up much more directly with other electronic textbooks and other sources of information on the web, fit much more efficiently into a wider curriculum, and allow the university&#39;s contributions to students&#39; knowledge to be carried forward much better after graduation. 
     Presenting Complex Knowledge in Depth: 
     Embodiments of the invention precisely satisfy the requirements expressed in the following passage from the Background: “The decentralized global research enterprise and the proliferation of shared knowledge on the web are overwhelming the adaptive capabilities of education based on printed textbooks. Linear outline and linear page sequence are the joint organizing principles of a printed book. Of course a book can also offer one or more separate lists of specialized items like figures or exercises to supplement the outline. However, there is no systematic means for rendering relationships between topics that cut across different segments of the outline. Nor is there any good way of highlighting the collective importance of relationships or themes that spread across different segments. Nor is there any good way of navigating through the book to see only those sections that deal with a single theme in the proper order. The tools presently available in a printed textbook to present complex material and promote understanding of complex matters are essentially limited to interpolated comments and diagrams, themselves trapped in the linear sequence of the book and visible only at that one point. Thus, there is a clear need for an electronic textbook that is built around the concept of a fully general non-linear outline that can make visible arbitrary relationships and present distinct traversal paths for each of the diverse themes presented in the book. There is also a need for an overlay system in the electronic textbook that allows faculty and students to add and share comments at any point in the book and fully general traversal paths through the book.” 
     Linking Electronic Textbooks to References: 
     A popular modern higher education electronic textbook could potentially provide a superior access point to relevant literature. This service could well be a boon to authors and publishers, and could be readily achieved by an author. To be viable, this service must give the student direct access to the cited references. Success will also depend on keeping the textbook up to date at reasonable cost while continuing to offer direct and immediate access to current references. 
     Direct Access to References: 
     “Direct Access” can be implemented to three degrees: access to the reference as a whole, or better direct access within that document to the point where the specific passage cited resides, or possibly the added optional capability of native presence at the website serving the reference, beginning from the point where the reference resides, with the option of direct return at any time to point of departure. The electronic textbook can provide this access to qualified servers, including access in all degrees to another electronic textbook. Once electronic textbooks have demonstrated this capability, it will become feasible for providers to serve the referred materials to these degrees, allowing linking to a specific passages and optional native access when appropriate. 
     Stand-Alone Overlays 
     These overlays are also useful in building a multi-course curriculum of study, involving multiple electronic textbooks as discussed above. A teacher, such as a university professor, or an entity such as a university department (or alternatively a school, school district or other similar user as discussed above), may wish to distribute a set of course materials tailored to that teacher or department&#39;s curriculum, without distributing an entire set of electronic textbooks for the curriculum. By providing a separate overlay, the teacher can build a single comprehensive set of comments, notes or other study aids, or even connections or paths, which correspond to the nodes of a number of electronic textbooks, and which address all of the electronic textbooks in a cohesive manner. This overlay can be distributed to all of the students. The students then separately purchase the underlying electronic textbooks. The overlay automatically links to each of the underlying electronic textbooks as they are acquired by the student. This functionality depends on common standards that are adhered to both in the overlay builder and in the electronic textbook. 
     Integrating Multiple Electronic Textbooks in a Curriculum: 
     In an embodiment of the invention, electronic textbooks can cross-refer seamlessly. For example, a course assigns two electronic textbooks, with closely interwoven material, such as a History of Labor Law and a History of Organized Labor. The student has access to both books, and has a Textbook Reader. Some years earlier, the present Instructor, while a graduate student assisting in this course, prepared an overlay  41  with a study guide and readings path, which he now distributes to the students. The overlay  41  includes the sequential path of the course readings through these two books. Each step takes the student to the precise point in the relevant book where the reading begins and provides a later marker for the conclusion of the reading. The four elements involved (the text reader, overlay  41  and the two electronic textbooks) interact seamlessly. Further, suppose that one of the books refers to the other during the reading. The student can then follow the highlighted link into the second book and return after reading the cited reference. The overlay  41  is a superior teaching aid in a lasting format that functions at the detail level. It serves as an umbrella above two or more electronic textbooks, guiding students through a curriculum that extends across them. Even without the aid of the overlay  41 , in an embodiment the two electronic textbooks can interoperate in the sense of offering direct access for cross-references: following a reference in one textbook will take the reader directly to the cited passage in the other and also provide native presence in the other book in case the reader chooses to browse it before returning to the original point where the reference was cited. 
     Overlays can Outlast their Textbooks: 
     The stand-alone character of the overlay is an advantage as time passes and textbooks change. The task of remapping the overlay to a new textbook may be supported automatically by the publisher by providing a suitable mapping from old to new pages, and otherwise it can be quickly accomplished by comparing old and new texts. During this same process additional elements can be added to the overlay to incorporate innovations in the new text, and notes concerning any useful material that has been lost can be directed to another source or in the worst case point to the older version. In this manner, an entire multi-course curriculum can be integrated into a single overlay. This overlay can then be offered to any interested users, including both current students and alumni. This allows the alumni to refresh and update the knowledge they acquired when they were students. 
     Carrying Knowledge Forward: 
     Institutions of higher education are natural places for energy to be invested in organizing and presenting knowledge in an integrated format, and it makes good sense for them to build upon these efforts to provide lifelong educational services for their graduates. The natural approach is a “living curriculum” in the form of overlay and supplementary material provided by the faculty that organizes and presents the information in electronic textbooks which are themselves being regularly updated. A setting of that kind can shelter and support ongoing communications among faculty as they share their academic learning, as well as knowledge learned through experience, to students and graduates in a relevant way. Academic compilations of this kind, building upon regularly updated electronic textbooks as their springboard, might become the foremost guides to professional information on the web. 
     Overlays on Existing Collections of Information: 
     The embodiments discussed above are directed to electronic textbooks. The nodes  10  are related to educational material compiled by an author of an educational textbook, and the connections  7  and paths  12 ,  14 ,  16 ,  18  are made by authors and users of educational textbooks. In additional embodiments, the principles and concepts discussed above can be applied to other collections of information. For example, the overlay discussed above can be created and applied to any existing collection of information. 
     Web Browsing Overlay: 
     In an embodiment, the overlay containing a user&#39;s path through a collection of information, with the user&#39;s comments, is associated with a plurality of nodes that represent items of information stored on a network, such as web pages stored at various locations on the Internet. This overlay is particularly useful in the context of web pages on the Internet, because each of those pages is typically controlled by different authors. Thus the content on the pages themselves cannot be modified by other users. However, the overlay of an embodiment of the invention allows a user to track his or her paths through a collection of web content and provide comments that help the user or other users understand the user&#39;s thought processes in navigating through the web content. 
     Recording a Product Search: 
     For example, a user is searching the web content to locate a desired object, such as a new car. The user has many different requirements for the new car, which are difficult to satisfy with a single product. Thus, the user does a lengthy search and review of many different cars described in many different web pages on the Internet. The user wishes to retain a record of his search, including not only the pages he visited, but also his comments reflecting, for example, his thought processes for why he chose to visit each page, his conclusions upon visiting each page, the alternative pages he considered visiting next, etc. The user may use this record to aid in his own recollection of the steps he took in searching for the object. Alternatively, particularly where the user was doing the search for someone else (e.g. the user was a shopping consultant or agent for the buyer), the user can provide the search history with comments to the buyer, so that the buyer can fully understand the search process, and can easily re-visit some or all of the material searched, with an understanding of why that material was deemed useful or important. 
     Browser Add-On: 
     In an embodiment, as shown in  FIG. 7 , the user  30  uses a computer  32  having a browser to search content stored as a plurality of pages  34  in a plurality of locations  36  on a network  38  such as the Internet. The browser includes an add-on  40 . The add-on  40  monitors the user&#39;s navigations through the pages  34 , as the user searches for the desired object. The add-on  40  is configured to record the user&#39;s path through the pages  34 , documenting each page  34  visited, and each connection between the pages  34  that the user navigates. These connections may be explicit links defined in the respective pages  34 , which the user clicks on. Alternatively, these connections may reflect locations of the pages visited, such as a URL, which the user enters into the browser, without traversing an explicit link. 
     Turning to  FIG. 8 , the pages  34  can be viewed using a browser running on the user&#39;s computer  32 . The browser includes an add-on  40 , which extends the features of the browser in accordance with embodiments of the invention. This add-on  40  can also incorporate the features of the overlay builder  56  discussed in further detail below. The content is displayed in the browser window  42  which displays the content of the various pages  34  at the locations  36 . The browser also permits the user to navigate to new pages using addresses entered into an address box for the browser window  42 . 
     Path Taken: 
     The add-on  40  contains a path-taken window  43 . This window shows the path the user has followed thus far, to arrive at the page  34  displayed in the browser window  42 . The path can be displayed either in text form, or preferably in graphical form as shown in  FIG. 8 . In an embodiment, the node in the overlay  41  corresponding to the current page  34  being displayed is highlighted in the path-taken window  43 , for example by being bolded, with an arrow indicating that the content of the current page  34  is displayed in the browser window  42 . 
     View Ahead: 
     The add-on  40  also includes a view-ahead window  44 , which shows the user the nodes, and/or pages  34  that are visible from the current page  34 . If the user  30  is following a previously created path through the overlay  41 , then the view-ahead window  44  will display the nodes in the overlay  41  which are visible from the node corresponding to the current page  34  being viewed. If the user  30  is not following any pre-existing path, and is instead creating a new overlay  41  or extending an existing overlay  41  by navigating to new pages  34 , then the view-ahead window  44  can alternatively display all of the pages  34  accessible from the current page  34 , or can be blank, signaling to the user  30  that a new path is being formed. 
     The view-ahead window  44  can display the connections from the current node and/or page  34  in different ways, depending on the nature of the connection. For example, sequential connections on a path being followed by the user  30  are displayed with emphasis (e.g. bolded or solid lines), whereas logical connections to other nodes are displayed with less emphasis (e.g. dashed lines), and other visible nodes may be displayed with even less emphasis (e.g. grayed out). Links in a page, which have not yet been converted into connections of the overlay  41 , are preferably displayed in a manner that distinguishes them from the connections of the overlay  41 . In the view-ahead window  44 , as well as in the path-taken window  43 , the user  30  can access information about the nodes in these windows by, for example, moving a cursor over the node, causing information, such as a comment or summary of the node&#39;s content, or the location of the node, to pop up or be displayed in the add-on  40 . The user can navigate to any node displayed in either window simply by clicking on the node in the respective window  43 ,  44 . 
     Comments, Index and Navigation Tools: 
     The add-on  40  also includes a comment view window  46 . This window displays comments pertaining to the current node being displayed, and permits users to add or edit their comments. The add-on  40  also includes an index window  47 . This window displays an index of terms in the overlay  41 , for use as discussed herein by the user  30 . Finally, the add-on  40  includes a navigation tools window  48 . This window displays any tools used by the user to navigate the content in the overlay  41 . This window  48  contains a search tool, for the user to search the overlay  41 . The window  48  contains a global view button, which allows the user to display a graphical view of the entire overlay  41 , or alternatively those portions of the overlay  41  which are accessible or visible to the user (e.g. depending on the user&#39;s role, and the visibility metrics discussed above). The window  48  optionally contains an external content button, which allows the user to navigate to external content, not found in the electronic overlay  41 . Alternatively, the existing navigation features of the browser window  42  allow the user  30  to navigate to any accessible content on the network  38 . As discussed in further detail herein, this external content is accessed by the user and stored in the overlay  41 . The window  48  contains a load new path button, which allows the user  30  to load a new path, or a new overlay  41 , into the add-on, for example when the user  30  wishes to review a path or overlay created by another user as discussed herein. Finally, the window  48  contains an add comment button, which allows the user to add a comment to the current node, or, when the user navigates a connection, to that connection. The windows of the add-on  40 , may optionally be hidden from view and only displayed when selected, for example from a menu, by the user. 
     Building the Overlay: 
     The add-on  40  builds an overlay  41 , as described above, which documents the user&#39;s path through the pages  34 . The add-on  40  records every aspect of the path the user  30  follows, including information such as the locations  36  visited, the pages  34  visited, any additional data the user  30  supplied such as information entered into forms on the pages  34 , or selections made on the pages  34 . This information is saved securely, using known methods of securing data such as encrypting the information. The add-on allows the user to enter comments for each page  34  visited, and each connection between the pages  34  on the user&#39;s path through the pages  34 . These comments, as discussed above, can be text, audio or video comments. The user  30  may select a button on the add-on screen to initiate entry of a comment, or alternatively may use other means of signaling the add-on to accept a comment, such as a special keystroke combination. 
     Sharing the Overlay: 
     The overlay  41  is then available for the user to distribute to other users, in the same manner as discussed above. The overlay  41  is also available for the user  30  to update with additional content or comments, should the user  30  re-visit the search at a later date. Thus, the user  30  can bring up a prior search in the add-on  40 , and pick up where the user left off, or at any point in the search. The add-on  40  preserves the entire search history in the overlay  41 . 
     Reviewing the Overlay: 
     The user  30  may also use the add-on  40  to bring up the overlay  41  for review after the user has completed a path through the collection of information. The user  30  can replay the path, re-visiting the pages  34  and the connections stored in the overlay  41  between the pages  34 , and also revisiting the comments stored with each page  34  or connection. The comments will automatically be presented to the user as the user traverses the pages  34  and connections while replaying the path. Other types of connections, such as the logical connections discussed in more detail in the next paragraph, are also presented for viewing in the replay of the path. 
     Extending the Overlay: 
     The user can also add additional connections which reflect relationships other than a traversal between two pages  34 . For example, if the user  30  identifies a logical relationship between two pages  34 , which the user did not at first appreciate as he was traversing the pages  34 , the user can add a logical connection between the two pages  34 , and provide a comment explaining why the user added the connection. Thus, in the car search example, the user could add logical connections that connect together all of the identified cars in the search which have the same color, or the same body style, or the same brand. Another user could then easily review only the cars having a given characteristic, such as 4-door sedans, but still visit them in a particular order as desired by the user  30 . This allows the user  30  to create entirely new paths in the overlay  41 , to relate the pages  34  in new ways. 
     A Map of the Path: 
     The user can also view the overlay  41  as a map of the user&#39;s path, using the add-on  40 . This allows the user to edit both the path and the comments. For example, the user can remove pages  34 , connections or comments which are no longer needed. The user can also add further comments to the pages  34  or connections. The user can also print the path. The add-on prints the path sequentially, to reflect the order the user  30  visited the pages  34 . The comments are printed along with each visited page  34 , or connection between pages. Audio comments are optionally transcribed to written form by voice-recognition software using known methods. 
     Inserting Material: 
     The user can also add additional pages  34  (or nodes  10  as discussed above), containing content not found on the network  38 . For example, if the user  30  has additional content stored locally on the computer  32 , the user can add this content to the overlay  41 , and create connections to the pages  34  already in the overlay  41 . This is similar to the process described above for a student adding in personalized content such as the node  10   j  to the electronic textbook embodiment. 
     Saving the Overlay: 
     In an embodiment, the overlay  41  saves the path in a compact form, such as retaining only the URLs for the various pages  34  visited, along with records for the transitions between the URLs. Alternatively, the overlay  41  creates an image or local copy of each page  34  visited, and saves a complete summary of the path the user  30  took through the pages  34 . 
     Sharing and Cooperating: 
     Because the overlay  41  is saved electronically, it can be easily distributed to other users, for example by e-mailing the overlay  41  to the other users, or placing the overlay  41  in a centrally-accessible location as discussed above with reference to the electronic textbook  5 . These other users can then use add-ons  40  on the browsers running on their computers  32 , to replay the paths in the overlay  41  as discussed above, as well as add their own comments, extend the paths in the overlay  41  to cover additional pages  34  on the network  38 , or supply additional local content. The users then can exchange the overlay  41  amongst each other, further building on the shared knowledge base. Eventually, the overlay  41  would include the comments and recommendations of a large number of users, as to which pages  34  contained desirable information. Each user&#39;s comments and additions are tracked. This allows any given user to easily identify which comments or additions were made by each user, and to filter this material based on who provided it. 
     Reliable Backtracking: 
     Because the overlay  41  tracks the user&#39;s interaction with all of the pages  34  on the network  38 , the overlay  41  allows for a more robust navigation of these pages  34  than is possible with just the web browser running on the computer  32 . For example, web browsers typically provide a “back” button for users to use to return to the page  34  they previously visited. Such browsers can even store a chain of previously visited pages  34 . However, this stored chain of pages is unreliable, because conventional browsers cannot reliably handle all types of web content. For example, if the user  30  navigates to a popup window, a conventional web browser will not retain the popup in its list of visited pages  34 . Thus the user  30  cannot backtrack to the popup window. Other forms of complex pages  34  are also not typically retainable by conventional browser histories, and cause the backtrack trail to be broken, disabling backtrack capability entirely. 
     The overlay  41 , in an embodiment, however, records all of the pages  34  visited by the user  30 , including popup windows or other complex pages not captured by browsers. The overlay  41  also keeps track of the browser&#39;s backtrack status as each new page  34  is loaded. When the browser loses backtrack capability, the overlay  41  records that event, infers an explanation (for example by receiving a signal from the browser indicating what the browser was doing when backtrack was lost [e.g. opening of a popup, opening an additional window in the browser, or changing the url without notifying the browser of intermediate activities]. The overlay  41  next identifies the proper chain of pages visited [e.g. correctly identify a popup or a new window or the initial and subsequent urls at a complex or secure website that the browser cannot track on its own]) and flags the node in the overlay  41  corresponding to the page  34  where backup capability was lost. Thus, if the user  30  later wishes to return to any visited page  34 , the user  30  can use the overlay  41  to get there. The overlay  41  reaches the pages on the continuous path using the browser&#39;s backtrack capabilities. Any page after backtrack capability was lost is recovered, for example by returning to the node corresponding to the page  34  where backtrack capability was lost, and then navigating forward through the nodes of the overlay  41 , along the recorded path, to reach the desired page  34 . 
     Submitting the Overlay to a Search Engine: 
     The overlay  41  can also be submitted to a conventional search engine such as www.google.com, to obtain additional guidance. The comments in the overlay  41  are optionally filtered out by the add-on  40  prior to submission, to preserve privacy. The overlay  41  is then parsed by the add-on  40  to extract the key terms and motivations underlying the creation of the overlay  41 . Those terms are formatted for presentation to the conventional search engine. The search engine results are then made available as additional pages  34  for the user  30  to traverse, to further extend the content in the overlay  41 . When multiple users of the overlays  41  each submit their overlays  41  to the conventional search engine, those key terms and motivations become part of the formula used by the conventional search engine to retrieve results. Thus, the submissions to the conventional search engine indirectly create a community of users  30  who are interactively aiding each other in building improved overlays  41 . 
     Mapping Across Multiple Content Collections: 
     In an embodiment, the overlay  41  is further used to create a map or overlay that shows the relationships of content in multiple different content collections, such as multiple different websites. The overly  41  is constructed, for example, by a website builder who wishes to correlate content on one website with related content on another site. The overlay  41  shows relationships (as connections) between the other sites&#39; web pages to pages on the present site, as well as relationships among the pages on the other site, and provides informative comments (for example as tooltips tied to the elements of the overlay  41 , or to the other pages, or as comments in the comments window  46 ). The other sites&#39; pages are represented as nodes in the overlay  41 . The relationships depict graphically the specific connections among the various pages and their material. This form of overlay is analogous to a personal navigation, but offers such features as links between local content and content at other sites, graphical displays of interconnections coordinated with local content, and a more professional style of presentation. The overlay  41  of an embodiment makes this approach readily accessible to website builders. 
     Facilitating Interoperation Among Websites: 
     For example, the overlay  41  allows websites to interoperate. Suppose that one website offers practical services and has developed a large clientele in some special area, while some other websites in that area offer useful information for that same clientele. The service-oriented website can prepare an overlay  41  that reaches key pages from the other sites, and integrates them into a guide for its clientele. When a user navigates to one of the pages residing at a foreign site, three special benefits can be offered: first, a helpful introductory comment places the foreign webpage into the context of the guide; second, the foreign website page comes up with customized emphasis on the key material that is being referred to; third, although the user is now operating native on the foreign site and can tour its webpages freely, at any time the user can use a control panel or special keystroke to return to the exact condition at the home website that prevailed before navigating to the foreign site. Note that the first and third benefits can be offered by the overlay  41  operating on the home website only. However, the second benefit is best realized by interoperation between two overlays  41 , one on the home website and one on the foreign website. Such interoperation can also offer a customized tour of the foreign website, using the overlay  41  on the foreign website, navigating from page to page highlighting relevant information. 
     Overlay for Legal Argument: 
     As discussed above, the overlay  41  can draw on network content such as web pages  34  on network  38 . Additionally, the overlay  41  can draw on local content stored on the computer  32 . Furthermore, the overlay  41  can draw on any other content that is accessible to the computer. For example, with reference to  FIG. 9  a user  50  uses a computer  32  to access a variety of content  52 , such as text or images of text, in a digital library  54 . The content  52  represents source material that the user  50  will use to craft, for example, a legal argument, a legal brief, or a position paper for a political debate. The user wishes to marshal the legal or political precedent for his argument, as well as the precedent he anticipates the opposing party to marshal. 
     The user  50  uses an overlay builder  56  to build an overlay  41  that assists the user in marshaling his precedent. The overlay  41  will be shared with other users, as discussed above. The overlay builder  56  can be an add-on to a browser, such as the add-on  40  discussed above. Alternatively, the overlay builder  56  is a stand-alone program running on the computer  32 . The overlay builder  56  displays the content  52  of the digital library  54 , and also displays a visual representation of the overlay  41 , including the nodes and the connections as discussed above. In an embodiment, the overlay builder  56  is itself an application of the same concepts used by the end users discussed above to navigate through content. The same components that a user uses to navigate through content are here used by the author to build the content. 
     Assigning Attributes: 
     In the overlay  41  of this embodiment, the nodes each contain a particular position or argument that the user  50  wishes to include. Each node has attributes assigned to it, for example the polarity of the position or argument (e.g. supporting the user&#39;s argument, supporting the opponent&#39;s argument, or neutral). Other attributes can include, for example, a measurement of the strength of the argument, a measurement of the likelihood that the argument will come up in the legal proceeding or the debate, and whether an argument has been disclosed to or is known by the other side and if so in what form. 
     These attributes can influence the appearance of the nodes as displayed in the overlay builder  56 , for example by shape of the node, size of the node, color of the node, or relative location of the node in relation to other nodes. For example, if the user  50  wishes to view the polarity of the various nodes in the overlay  41 , the user selects the polarity attribute and tells the overlay builder  56  to display the different polarities in different colors. 
     Attributes in an Electronic Textbook: 
     Similarly with respect to the nodes  10  discussed above in the electronic textbook  5 , attributes of the nodes  10  can influence the appearance of the nodes  10  in the electronic textbook  5 . Thus, nodes  10  can have attributes such as title, brief abstract, type (e.g. feature format (including various kinds such as text, image, mixed, interactive, video, audio, etc.), gateway, vestibule, gallery, logic view, or ordinary junction), and significance level (a number from 1 highest to 9 lowest, like the levels of an ordinary linear outline) that helps to present compact summaries of the global text or local region by selectively showing only higher levels. These attributes may similarly be displayed, either by the overlay builder  56 , the browser add-on  40 , or by the electronic textbook  5  itself, using the shape of the node, size of the node, color of the node, or relative location of the node in relation to other nodes as discussed above. 
     Importing Material from Prior Overlays: 
     In addition to source material, the content  52  of the digital library  54  can also include other overlays that were previously generated by the overlay builder, for example for an earlier aspect of the legal case, or for a similar case or debate position. The overlay files are stored for subsequent use in the digital library  54 . In an embodiment, the overlay files are stored in a directory, similarly to the way that pdf files are stored, or they may be stored as indexed items in a digital library with its own index of items (such as pdfs and overlays), each with their appropriate searchable attributes. When a previous overlay is brought up, it can be viewed as rows in a spreadsheet or relational database (the “tabular grid” presented below), or can be presented to the user visually as a map similar to the textbook  5  discussed above (the “display field” presented below). 
     The user  50  thus can begin with an existing overlay, and modify it to comport with the user&#39;s current needs, by deleting unwanted nodes, connections or comments, or changing attributes of the nodes, connections or comments, for example by raising or lowering a relevancy attribute, a strength attribute or a likelihood of presentation attribute. This feature of an embodiment of the invention allows the user  50  to easily preserve and re-use his prior work. 
     Importing Content 
     In an embodiment, as the user  50  researches the issues for relevant content, such as relevant precedent, the user creates new nodes simply by selecting the desired content from the content  52 , and dragging and dropping that content  52  into a display window of the overlay builder  56 . The overlay builder  56  creates a new node in the overlay  41 , containing the exact passage selected from the content  52  (assuming that the digital library  54  supports this). Alternatively, the new node in the overlay  41  contains the entirety of the content  52  selected. 
     Selecting the content  52  causes the overlay builder  56  to present the user  50  with several options, for example: (1) bring in the selected material as a quotation, (2) create a citation to the material, (3) create a footnote containing the material. The user  50  then indicates via a comment which portion of the content  52  is pertinent to the position or argument defined by the node, and indicates by selection the exact material that is relevant. The overlay builder  56  also tags the new node with the path to the source content  52 . The overlay builder  56  also automatically populates attributes of the new node with any attributes that can be gleaned from the source content  52 . For example, bibliographic information about the source content  52  is collected, and a timestamp for when the node was created is provided. If the user  50  wishes to revisit the source content  52 , the user simply clicks on the node, and the overlay builder  56  retrieves the source content  52 , opened to the proper location with the selected passage highlighted. 
     Characterizing a Newly Created Node: 
     When the user  50  creates a new node, the overlay builder  56  causes a prompt such as a menu to appear, requesting the user  50  to provide additional information about the node, such as a title for the node, attributes of the node (as discussed above), and any comments the user  50  wishes to attach to the node. If the user  50  wishes merely to cite particular content  52 , without any verbatim quotations of the content  52 , then the user  50  need not associate any of the actual content  52  with the node. Instead, only a connection to the content  52  is provided, indicating the specific citation to the content (e.g. page and line number, or footnote number). The content  52  is still available for the user  50  to review, by clicking on the node as discussed above. The overlay builder  56  then creates the connections to the new node. A connection can be automatically created, to the last node that was added. Additionally, the overlay builder  56  can prompt the user  50  to provide any additional desired connections, as well as provide comments for each such connection. 
     Logical Connections: 
     As discussed above, the connections between nodes in the overlay  41  can be of several different types (e.g. logical connections, sequential connections). In this embodiment, the logical connections can represent, for example, implication and contradiction, or affirmation and refutation. The sequential connections can represent the sequence of the user  50 &#39;s presentation, or a projected sequence of presentation of an opposing party. The overlay  41  displays each of these different types of connections in ways that make clear their distinct roles. Thus, a logical connection is displayed differently from a sequential connection (e.g. a dashed line vs. a solid line). The connections in the overlay  41  may be one-directional, or they may be bi-directional. Each of the connections between two given nodes include their own comments, which can range from a simple title of the connection, to a short note, to a rehearsal of a complete argument related to the transition between two items of content  52  associated with the two nodes joined by the connection. 
     Uses for Temporary Paths: 
     The user  50  can create as many paths through the nodes in the overlay  41  as desired, and can add or delete a path at any time. For example, when the user  50  invites another user to review the overlay  41  or an aspect thereof, the user  50  can create a temporary path through the overlay  41 , which takes the other user through only those nodes and connections that are relevant to the review. This concept applies equally to the web search and electronic textbook embodiments discussed above. Thus a search consultant can create a temporary path through an overlay  41  representing a web search, to highlight for example just the models of car that the search consultant located. Additionally, a teacher can create a temporary path through selected nodes  10  of the electronic textbook  5 , to help a student understand a specific point of instruction. 
     Creating a Path by Traversal: 
     Inserting a new path into an overlay  41  is preferably done simply by traversing the nodes in the overlay  41 . The user  50  clicks on the nodes in the order desired to form the new path. Deleting or moving a connection or a path is equally straightforward. The user simply selects the connection to be deleted and indicates a desire to delete it, for example by selecting “delete” from a menu or by striking a key on a keyboard of the computer  32 . The user can move a connection or path by dragging and dropping the connection to the desired nodes, or by deleting the undesired connection or path and creating the desired connection or path via traversal as discussed above. 
     Viewing a Message Sent as a Temporary Path: 
     When the other user proceeds along such a path, they will see the comments provided by the user  50 , as well as the transitions between the nodes that express the user  50 &#39;s thoughts and questions, so that the other user can quickly understand the user  50 &#39;s intentions. The overlay  41  is also set to automatically open for the other user at the starting point of the temporary path created by the user  50 , to allow the other user to quickly get started. Should the other user wish to gain additional perspective on the overlay  41 , the other user can use the overlay builder  56  (or the add-on  40  or electronic textbook  5 ) to explore the rest of the overlay  41  (or electronic textbook  5 ) to gain the necessary perspective. 
     Printing a Sequential View of an Overlay Path: 
     The overlay  41  can be printed, to generate a conventional, sequential copy of the argument formulated by the user  50 , or a legal brief. The user  50  simply instructs the overlay builder  56  to print the sequential path the user  50  defined through the overlay  41 , reflecting the user  50 &#39;s argument or brief. Preferably, the user  50  first views the overlay  41  in the overlay builder  56 , for example in a preview mode of the display field  60 , to confirm that the selected path is providing the correct nodes and connections. The connections and nodes in that path will be printed in sequential order. The nodes represent citations to and quotations from the authority relied upon. The nodes can also represent certain prepared arguments. The connections will represent transitional paragraphs between citations, for example providing additional explanation or argument which relies on the citation. The nodes and connections can be printed in whatever format is specified by the user  50 . For example, the nodes can print full quotations or just citations. The nodes can print as footnotes in the printed document, or as paragraphs of text. 
     Printing an Overlay Path from an Electronic Textbook: 
     Of course, this same concept applies to the embodiments described above. Thus, a conventional textbook can be generated from the electronic textbook  5  by printing out a path (e.g. paths  12 ,  14 ,  16 ,  18 ) in sequential order. An annotated search history can also be generated by printing out a path through the overlay  41  of  FIG. 7 . The same overlay  41  or electronic textbook  5  can generate a large number of different conventional copies or books, simply by selecting and printing any of the different paths through the electronic textbook  5  or overlay  41 . 
     Visual Logic: Displaying Structured Argument: 
     The overlay builder  56  also aids the user  50  in mapping out his argument strategy and thought process, by presenting a visual representation of the salient arguments, positions, and authorities. Thus the user  50  can view various perspectives on a given overlay  41 , or a path through that overlay. As the user selects a given path through the overlay  41 , the spatial orientation of the nodes in the overlay  41  change, to emphasize the selected path. For example, if the user  50  displays the path representing the user  50 &#39;s argument, then all nodes which are not in the user  50 &#39;s argument, such as those that pertain to the opposing party&#39;s argument, are re-positioned in the display of the overlay builder  56 . These other nodes can be displayed for example as side-notes in proximity to the selected path. Thus each node or connection in the selected path may have a side-note showing the refutation the other party is expected to make on one side, and any supporting points (but which are not directly part of the user  50 &#39;s argument) as a side-note on the other side of the display of the overlay builder  56 . 
     The user  50  can, of course, also display the other side&#39;s projected argument as the selected path, with the supporting and refuting points to the opposing party&#39;s argument being displayed as side-notes. The user  50  can also display both sides&#39; paths in parallel, and emphasize the logical connections between the respective arguments. 
     Display at Various Levels of Detail: Assigning Outline Levels: 
     The user  50  can also provide additional structure to the overlay  41 , by assigning significance levels to nodes and creating higher level nodes which themselves encapsulate other nodes. Thus the user  50  can create a hierarchical layering of the nodes in the overlay  41 . This allows the user  50  to group related nodes together, and display the overlay  41  at varying levels of detail, converting the overlay  41  into a non-linear outline. When a collection of nodes is grouped together, the connections between nodes within the group are not displayed in the overlay builder  56 . However, connections to nodes outside the group are still displayed. Optionally, where there are multiple connections between two higher-level nodes, those connections are coalesced into one connection for display purposes. These higher level nodes can be expanded and compressed as desired, to allow the user  50  to view and analyze the overlay  41  at any desired level of abstraction. This allows the user  50  to create an outline view or views of the overlay  41 . Because the overlay  41  can contain multiple paths, all of the various paths from one higher-level node to another (paths which pass through various lower-level nodes) are simply paths as defined in the overlay  41 , and can be straightforwardly displayed, as in the examples above. Of course, additional comments can be provided for any of the higher-level nodes or connections created as part of this outline. Similarly, this concept can be applied to the other embodiments discussed herein. 
     Other Layers: Expressed and Hidden Arguments: 
     Similarly, the user  50  can define layers for the overlay  41  (or electronic textbook  5 ). A layer is a group of nodes and connections that are all related to each other in some fashion. For example, the user  50  may wish to distinguish between positions that the user  50  has already expressed, and those positions that are still hidden from the other side, or distinguish between the other side&#39;s expressed positions and the user&#39;s conjectures as to the other side&#39;s hidden positions. The user  50  might also want to add a layer for predicted resolutions of various points of disputes. 
     Assigning Layers to Paths in the Electronic Textbook: 
     Similarly, for the electronic textbook  5  discussed above, the author may wish to define separate layers for each of the paths  12 ,  14 ,  16  through the electronic textbook  5 , or define a separate layer for each stage of a multi-class curriculum or course of study. The overlay builder  56  allows the user to select a given layer (or layers) to emphasize visually, such as by highlighting the layer, expanding the size of the layer, or moving the layer forward in relation to other layers. Non-selected layers can be removed from the visual display region of the overlay builder  56  entirely. 
     Querying Content Through Temporary Connections: 
     When creating an overlay  41  (or an electronic textbook  5 ) the author may use the overlay builder  56  to assist with the creative process, for example by searching and querying the underlying content (e.g. pages  34  or content  52 ) used to build the overlay  41  or electronic textbook  5 . The overlay builder  56  accepts queries on the content, and uses those queries to build temporary connections to and between the content queried. Similarly, the overlay builder  56  permits the author to query the nodes in the overlay  41 , and builds temporary connections between the nodes queried. When the author is done with a particular query, and has located the desired content or nodes, then the connections created by the query can be relegated, disappearing from the overlay  41  or electronic textbook  5 , at least for display purposes. The query remains, however, in an archive (e.g. another overlay created for archival purposes) for the author to refer back to when needed. 
     Temporary Development Connections: 
     Similarly, the author can, in building the overlay  41  or electronic textbook  5 , identify several nodes as logical alternatives to consider for use in the final overlay/textbook. This indicates that a future choice will have to be made. A list of these temporary development connections is automatically maintained, tracking their character and status. This list can be traversed sequentially. Tracking the history of its assembly is another way of navigating the overlay  41 . Of course, these concepts can be used by any user of the overlay  41  or electronic textbook  5 , not just an author. 
     Creative Development Environment: 
     The electronic books and overlays of embodiments of the invention, such as the electronic textbook  5  or the overlay  41 , are built using a creative development environment such as the overlay builder  56  discussed above. In an embodiment, the overlay builder  56  is a creative development environment for assembling, organizing, developing and sharing information. The overlay builder  56  is an electronic knowledge tool oriented towards effective thought. The overlay builder  56  interfaces with other publishing tools such as web browsers, word processors, desktop publishing software, document management tools and digital library software. The overlay builder  56  extracts content using these tools, and inserts that content into the nodes of the overlays and electronic books of embodiments of the invention. 
     Aids to Productive Thought: 
     The overlay  41  or electronic textbook  5  of embodiments of the invention are effective because they aid users in many aspect of their thinking, as discussed herein. They help the user, but they also help the author. Creating an overlay  41  or electronic textbook  5  helps the author think about the topic being addressed. Creative development in the creative development environment can enhance the author&#39;s work, even if the author ultimately is creating a conventional publication, in linear form, and does not intend to share the electronically developed content (e.g. electronic book or overlay representation). 
     Building Tools in Three Aspects: 
     Consequently there are three distinct aspects to the tools used in the overlay builder  56 : (i) developing knowledge and creating formal material; which can be supplemented by creating either an actual (ii) electronic textbook or other electronic book, or (iii) an overlay, electronic book or a website that combines the underlying content with the overlay, for release. Developing knowledge and creating material is the first step in any case. Beyond that, the later stages create electronic documents and also offer a potent feedback loop, as knowledge continues to develop while the material becomes embodied in its final form. 
     This suggests three embodiments: (i) Author&#39;s Workbench with Knowledge Development; (ii) the Electronic Textbook Builder, which is an extension of the Author&#39;s Workbench; and (iii) Website Builder, a parallel general tool for building overlays, electronic books and websites, also an extension of the Author&#39;s Workbench. 
     Author&#39;s Workbench: Knowledge Development: 
     Here the core benefit comes from the workbench providing aids to productive thought, as discussed in further detail below. Techniques are offered that profoundly improve coordination between visual and verbal analysis, allowing effective collaboration that benefits from their complementary capabilities. These same techniques and other methods also improve the alignment between conscious thought and broader mental activities. As a result, emotional blockages and biases are weakened and we open to new ideas with fresh discernment. 
     The effect of these benefits is magnified by the overlay builder&#39;s efficient coordination of diverse mental contributions. The author&#39;s workbench uses the overlay builder&#39;s tools to organize and ultimately assemble the raw material for a publication. The publication may be in a traditional linear form with a table of contents and outline, or it may be in electronic format, such as an electronic textbook  5 , an overlay  41 , or a web site accompanied by an overlay  41 . One body of material can be also be deployed in both ways: the traditional book is extracted from the electronic textbook  5  or the overlay  41  simply by creating a linear path and exporting it in text form, as discussed above. 
     Electronic Textbook Builder: 
     This is an embodiment of the overlay builder  56  that is specialized for creating electronic textbooks. It has all the capabilities of the Author&#39;s Workbench, with general capabilities relating to the connectors  7 , the halls of informed choice, the perspectives, and the other concepts discussed above with respect to the electronic textbook  5 . The electronic textbook builder embodiment deals with many special textbook needs. 
     As discussed in further detail above, the electronic textbook format allows the author to (i) attach interactive support functions to all nodes, and (ii) embed within specialized nodes extensive interactive content. Further, (iii) the electronic textbook allows interactions with the user to be recorded as attributes of the user&#39;s path through the electronic notebook that can be shared with friends, parents, teachers, the author, and so on. 
     Recording User Interactions: 
     Recording interactions with the user, which include such things as choices, comments, time spent in various nodes, performance on test your skills, serves a number of important functions such as guiding the user toward choices that result in finding their optimal book; 
     tracking the user&#39;s use of the book and performance with material in the book, and sharing this information with parent and/or teacher; 
     and giving the student an opportunity to share comments and questions with other students and offer them suggestions about nodes to visit in the book. 
     Interactive Support Functions: 
     The interactive support functions include: 
     view-ahead, 
     path-taken, 
     perspectives, and 
     overlay view (which displays the network of overlays, including the user&#39;s, parents&#39;, teachers&#39;, friends&#39; with the option to focus on a subset such as just one&#39;s own comments), 
     other navigation tools, 
     search, 
     index, and 
     the dialogues discussed above. 
     Specialized Nodes: 
     The forms of specialized nodes include: 
     junctions (gateways, vestibules, galleries, logic views and simple junctions), 
     test your skills, 
     examples, 
     exercises, and 
     interactive Aids to Productive Thought (APT) (which are interactive displays that help to align conceptual and intuitive understanding, make useful connections between related topics, assist in remembering and getting a feel for things, help with the creative process and with effective inference, and so on.) 
     Overlay Builder: 
     With reference to  FIG. 10 , the overlay builder  56  includes a display area  60 , in which the overlay  41  (or electronic textbook  5 ) is displayed while the overlay is being created. The display area  60  is also used to display a completed overlay  41 , and can be used by users to navigate the overlay  41 . Additionally or alternatively as discussed above, a browser add-on such as the browser add-on  40  is used by users to navigate the overlay  41 . The display area  60  is the Creative Development Environment is the visual display field, referred to as the “display field”. It is also a graphics workspace, where overlays can be assembled and the appearance of network displays can be crafted. It brings visual analysis (discussed in further detail below) to bear on the development of an electronic textbook  5  or overlay  41 . The overlay builder  56  further includes a text-based tabular array  61 , which in the Creative Development Environment is referred to as the “tabular grid”. The tabular array  61  serves as the verbal analysis tool (as discussed in further detail below). It also offers full capabilities for assembling an electronic textbook  5  or overlay  41 , and allows convenient entry of entities (i.e. nodes  10  or connections  7 , halls of informed choice, perspectives, etc.) and their attributes, as well as sorting and filtering attributes, nodes, connections etc. The display field  60  and the tabular grid  61  work in lockstep so that both modes of entry, display and analysis can be immediately engaged when appropriate. You will find that the Creative Development Environment closely corresponds to the user environment. In a way, this is analogous to film-making in the sense that the director/author at all stages of development and the audience/users both experience the final product in the same way, and in the sense that the director/author strives to anticipate the responses of the audience/user and hone the product to meet their needs. In this case, the final product is experienced primarily through the closely coupled display field and tabular grid. However, in this case there is a further and even closer correspondence because most of the author&#39;s tools for developing understanding of the material and composing the electronic textbook are also employed by the student user to learn from and study and personalize his or her version of the electronic textbook. 
     Functions of Display Field and Tabular Grid Serving both User and Author: 
     Users of the electronic textbook benefit from a non-linear outline, in the form of an overlay in multiple layers, presented in the display field; the author of the electronic textbook assembles this non-linear outline as the material is being gathered, and organizes the material using the same overlay in the display field or tabular grid. 
     Users of the electronic textbook are able to access and extend the non-linear outline in either visual or verbal formats, respectively the display field and tabular grid; the author of the electronic textbook conceives of and assembles the material for the textbook using the same formats, display field and tabular grid. 
     The electronic textbook user reviews the path already traced and explores options ahead observing views of the non-linear outline in the display field; the author of the electronic textbook uses the same views in the display field to design and test navigation paths and optional choices for users. 
     Users are able to use the display field and tabular grid to make personal notes on the items in the electronic textbook, add items to the electronic textbook and create connectors among these notes and items, for their own benefit or the benefit of others; the author uses the display field and tabular grid in the same way to create the non-linear outline overlay that determines navigation paths and options. 
     The electronic textbook user adds additional items to the electronic textbook using the display field and tabular grid and offers these to a privileged user or the author for inclusion in the textbook; the privileged user or author reviews the material suggested by the user, deems it worthy of inclusion, and uses the display field and tabular grid to incorporate it into the electronic textbook. 
     Users work in the display field to include diverse audio and visual media in their notes on items in the electronic textbook; the author uses the display field and tabular grid to assimilate various audio and visual elements in the electronic textbook. 
     The electronic textbook user employs the glossary to find the meaning of a term, and then uses the display field to view selected highlighted instances of the term sought; the author uses a list of terms in the tabular grid to sharpen up language and develop a glossary, and uses the display field to verify terms for the glossary by viewing selected instances of terms under consideration. 
     The user&#39;s understanding is heightened by links between items in the display field that demonstrate logical relationships—“visual logic”—or suggest important associations—“drawing with meanings;” the author uses visual-logic and drawing-with-meanings tools to explore complex interactions and elicit new ideas while simultaneously developing graphic material for the electronic textbook that the user will later view. 
     Overlay Tools: 
     Additionally, the overlay builder  56  has a suite of tools  62  available for use by the user to create, modify or view the overlay  41 . Example tools include tools to facilitate adding nodes or connections to the overlay, such as templates  62   a  that can be dragged and dropped into the display area  60 . The locations of the nodes and connections are similarly modified by dragging and dropping them into the desired new locations. The overlay builder  56  allows the user to define paths through the overlay  41  in the display area  60 , either by the user traversing the nodes and connections and viewing the content, or alternatively by the user merely selecting the desired nodes and connections from the display field, for integration into the path. Buttons, scrollbars and rotation tools  62   b  can be used to manipulate the overlay  41  in the display area, for example to zoom in or out, pan up, down, left or right, or rotate the view, or search the content of the overlay  41  or that connected to by the overlay  41 . The overlay builder  56  allows the author to save the overlay  41  as it is under creation, including saving snapshots of the overlay  41  in progress. These saved snapshots are archived for the author to return to as desired. 
     Using CDE Components: 
     We now turn to a discussion of the options available in a creative development environment of an embodiment of the invention, and the ways the options may be used to create electronic textbooks or overlays. 
     Features, Halls, Logic Views, Nexuses and Connectors: 
     In graphical terms, a “feature” is a node and a “connector” is a link between nodes. Also halls of informed choice, logic views and logical nexuses are other kinds of nodes where connectors converge. Features, Halls, Logic Views, and Nexuses are displayed as nodes in the display area  60 , while connectors are displayed as links. In the tabular grid  61 , these features are displayed as rows (or columns) in the display. 
     Here are some ideas about using features, halls, logic views, nexuses and connectors: 
     How do You Determine Features?: 
     If a topic is important enough to deserve to be in an outline, it should be a feature. Why? Because the network of features displayed in the display field  60  and the tabular grid  61  is like an outline, and you want the topic to be included in both areas. If the topic is a piece of a logical structure it should be a feature, so that it can appear in a structured display, such as a hall of informed choice. If the topic is going to receive connections from elsewhere, it should be a feature so that those connections can terminate in a node. 
     How do You Determine Halls of Informed Choice?: 
     These should appear at points where you want the user to pause and reflect. Gateways are points of entry for new visitors and/or transition between major sections. Vestibules are typically reached after the user chooses to set off in new direction: they encourage the user to pause for consideration and help the user to establish a personal context before proceeding. Galleries present comparable choices: any set of features that belong together in a list can appear in a gallery, and a gallery can also usefully collect a set of scattered features that share something in common. (For example, the set of instances of a given term or phrase are shown in a gallery.) Ordinary junctions are like trail junctions with a signpost. 
     How do You Determine Logical Nexuses?: 
     Here is an example: 
     You begin with important relationships among constructs, ideas that are important to your message. You plan to present their collective relationships in a logic view. These may be relationships of cause and effect, which are directional from cause to effect, or refutations that are directional with reverse implication. There also associations that tie two constructs together, which are bi-directional, and contradictions that are bi-directional in reverse. 
     It&#39;s likely that each of the constructs involved will deserve to be in the outline, in which case each becomes a feature in its own right and logical connectors can handle the relationships among them. But suppose that the relationships among the constructs are complex, so that there may be a number of separate factors on the same connector, and/or a large number of crisscrossing connectors. In that case the diagram may be confusing rather than helpful: to clarify it, look for underlying factors that participate in the relationships among the constructs. Each of those underlying factors may be involved with only a few constructs in straightforward ways. Therefore create a logical nexus for each underlying factor, connected to the features it relates with. 
     For example, suppose that six constructs are closely interrelated, with as many as twenty linkages among them. This could be depicted with 20 individual connections in a single logic view displaying all of those connections, but all the crisscrossing might be confusing. However, if the connections have six flavors that each correspond to an underlying factor, the diagram becomes much clearer when logical nexus nodes are created for the six underlying factors, and each factor is then connected to the constructs it relates to. This approach can visibly capture the essence of the logical linkages. 
     Finally, how do You Determine Connectors?: 
     Connectors are of several types. There are connectors that express intrinsic relationships between the features they connect. These are “associating connectors” because they relate to the meaning and content of the features. Some associating connectors will be logical connectors that actually represent logical relationships and meaningful associations per se, as discussed above. 
     Also every path is expressed as a series of connections between nodes that are stages in the path, and so connectors are the links between nodes in a path. Such connectors belong to their path: if another path includes that same connection, it will have a distinct connector. 
     A connector could also be a stage in a path, but that may be confusing because a connector is intrinsically a link and has no home location. Therefore it&#39;s preferable not to include a connector as a stage in any path, so if you see a need for this create an ordinary junction node before the connector to serve that purpose. 
     One special form of path is the sequential ordering that leads progressively from the first to the last item in a list. Sequential ordering is another function of connectors. There are connectors between a parent and its children, for instance the title of a list and the members of a list, or a node on one level of a tree and the nodes on the next level that branch from that node. 
     Organizing Material for Nodes: 
     Each node has a title and optionally a short abstract—typically a sentence or short paragraph. Beneath these is often text and images in web format. Every such node should have some material. There is no upper limit on the extent of material. Ordinarily each node will have its own material, stored separately for example as a separate page of content (e.g. a web page). However, children of a node can be placed together with the parent in the same content store (e.g. on the same page beneath their parent, with their own urls, titles and abstracts, in sequential order). 
     Text and Images for Nodes and Connectors: 
     Think of the title of a feature node as the title of a section in a chapter, and place below it whatever text and images belong to it. The material can be as extensive as needed. In an embodiment, the feature nodes have roughly the same amount of text as each other. Alternative embodiments allow them varying lengths based on the complexity of exposition in the node. 
     Connectors can have widely varying amounts of text, and may have none at all. Think of the connectors in paths as transitions, and provide as much text as necessary to clarify that transition in that path. When a path is printed (for example to create a linear book as discussed above), by default connector texts are printed in italics and feature texts in ordinary type. Reading through the printed version is a good way to see how well your connector texts fit in. Logical connectors that express relationships should have text (or images) to explain the nature of the relationship, and the text should be as long as needed. 
     Assigning Significance Levels to Nodes and Connectors: 
     One of the display options is to show the nodes down to a certain level. For example, the nodes can be organized as in linear outlines, with the highest level being one and the lowest being nine. When preparing a non-linear outline, it&#39;s very helpful to assign levels to significant nodes carefully, so that the layout of your network is clear at every level, and successive moves down to include lower levels add information across the board in a consistent way. 
     Halls of informed choice are typically assigned to the higher levels of the network, because of their important roles in navigation. A hall should typically not be at a lower level than the major nodes that it leads to. In this manner, when a user collapses the lower levels of the network, to more easily understand the higher-level organization of the material in the network of nodes, the user will not lose sight of an important hall of informed choice, until and unless the nodes the hall connects to are also collapsed. 
     Unless a connector is assigned a level, its level by default is the lower of the two nodes that it connects. However the display generally traces connections between high level nodes being displayed even when there is no complete connecting path at the levels shown, typically selecting the shortest connecting route and showing it with a lighter line corresponding to the lowest level of the connection along that route. 
     Points of Access: 
     It is sensible to design your material around access points and paths. Purpose-built gateway nodes are the primary access points. In the case of a website, internal web pages that are likely to be reached through search engines can also be viewed as access points. It is not necessary for an electronic book or overlay to have more than one access point or more than one path, but it is often preferable to provide alternate access points, to give users a variety of ways to experience the content, and to cater to a variety of learning modes as discussed above. Paths are routes that present valuable aspects of your material effectively to the audience that comes to them. Thus, an electronic book or overlay that has many different paths through it will provide an enhanced experience to the users. 
     Stages on a Path and Optional Features: 
     In a conventional book the stages are sequential, the path is linear, and the flow is like the unfolding of verbal thoughts. Viewed as a means of communication, a book invites the reader to journey through a landscape familiar to the author, who simultaneously narrates the journey and presents the landscape in a single stream of words. The author&#39;s adventure when initially developing this landscape is implicitly present at all times: the journey remains highly personal and yet in some sense it is fully shared. 
     The word “garden” suggests something quite different. As a visitor strolls through the garden, paths chosen, steps taken, eye movements here and there, thoughts and impressions collectively create a unique texture of experience. The continuity in which each sensory image is embedded is the visitor&#39;s own continuity, not the gardener&#39;s. The plants that have been laid out to grow in the garden shape it through their vitality. As a consequence the gardener is somewhat removed from the visitor&#39;s experience. In a way the gardener is a facilitator whose work is peripheral to the life of the garden. 
     It is helpful to think of the stages of the path in an electronic book or overlay of embodiments of the invention in the same way. Each has its own aspects of meaning, and should be well rounded. When as author you place a stage of a path (i.e. a node or a connection) in conjunction with other stages to achieve an effect, you are facilitating a variety of possible experiences for your users, none entirely predictable. 
     Optional features (such as the nodes  10   c ,  10   e ,  10   j , or the path  14   c  discussed above) represent possible excursions: the user can consider their qualities and easily decide whether to reach out to explore them or leave them aside. Their potential interest should be readily apparent from a brief abstract, presented for example as a tooltip to the user when he mouses over the node in the reader  21  or add-on  40  discussed above. That way the user can evaluate them without confusion, and keep the possibility in mind so as to possibly return later if some new association awakens an interest. 
     Visibility: 
     As author, you determine the visibility of nodes and paths, as discussed in detail above. Once the user has settled on a path, normally that entire path from beginning to end becomes visible, but you can set the parameters in a different way. You can also determine whether other paths are visible or not, and from which points on the present path they can be seen. You also determine which optional features are routinely visible from each point on the path. 
     Display Field and Tabular Grid: 
     The overlay builder  56  uses the display field  60  and the tabular grid  61  to construct the electronic textbook  5  or overlay  41 , and to incorporate the features, halls, logic views, nexuses, connectors and other aspects discussed above. The display field  60  and tabular grid  61  respectively reflect the visual and verbal workspaces, working together to facilitate the author&#39;s creative efforts. 
     Display Field: 
     The display field  60  is the visual graphics workspace for the overlay builder  56 . The same basic framework of the display area  60  is also used for the display of large-scale perspective displays of the content for readers, for example when the reader wants to get a perspective view of the entire textbook or overlay, or large portions of it. 
     Benefits of Laying Out Concepts Visually: 
     The overlay builder  56  allows you to display many aspects of conceptual thought visually. This capability has at least five significant benefits: prompting memory; aids in sharing your thoughts and cooperating with a team; offering perspectives that help you to notice errors and omissions; fostering creativity; and facilitating more effective thought. 
     Preparing Depictions: 
     The display field  60  can show perspective displays for a work in progress or a finished textbook or overlay. The display  60  can be initialized from the Non-linear Outline of the site, and edited or reshaped in any way as appropriate. The elements (e.g. nodes, connections, etc.) in the display can be moved around to new positions. The templates for the perspectives actually used in the published document will be laid out here in the process of development. Any given depiction of the elements of the textbook or overlay can be modeled in the display field  60  and then saved as a perspective. This is also a home page for editorial work. New features can be created, new connections added, paths created and extended and so forth. Features and connections can be edited. Halls of informed choice can be defined and edited. In the display field  60 , positioning of the various elements is important. Appropriate position is an aid to productive thought. Positions can be determined by mathematical algorithms or assigned by the author&#39;s judgment. 
     Positioning Algorithms: 
     Mathematical algorithms can arrange the nodes to as to minimize crowding of nodes and crisscrossing of connections. When the perspective centers around a specific location or path, the algorithms rely on distance from the center or centerline to develop an attractive layout. When the author has assigned significance levels to layer the nodes and connections, or has assigned any other kinds of layering, the algorithms take account of layering so that each layer is efficiently depicted. The algorithms are also very useful when adjusting the positioning after new nodes and connections have been added, nodes and connections have been removed, or the author has moved some nodes and connections manually. Algorithms also serve to “seed” a creative display field with raw material according to some existing structure, before the author begins a creative project. 
     Positioning by the Author: 
     The author can select the positions of nodes and connections for purposes of creativity and communication. In creative exercises described below such as the dwordle, drawing with meanings and visual logic, apparently random subliminal selection of positions helps the author to coordinate verbal and visual analysis. Communication of the underlying relationships among nodes is highly enhanced by positioning them in accord with their interrelations. We are familiar with positioning nodes in the two aspects of sequence and significance level in a linear outline, or laying them out in two dimensions in a diagram. The same principles apply here where linear outline and diagram combine in a non-linear outline. 
     Display Options: 
     Ordinarily the visual display field  60  shows features and connections between them in graphic form as nodes and connections. To encourage creativity, existing structure can be optionally hidden, or merely hinted at through color coding or spatial proximity. The primary display field  60  shows the global view of all nodes and all connections that are not path-dependent. Additional display areas  60  can be brought up for any desired custom display (e.g. of a perspective) and any given path. Most displays for users are also presented by default in the display area  60 , and the user thus sees them in the same way that the author does. To further facilitate this, the overlay builder  56  can include the features of the textbook reader  21  or the add-on  40 , as discussed above. 
     Tabular Grid: 
     The tabular grid  61  is the verbal and numerical workspace for the overlay builder  56 . Each node and each connector appears as an entity in the tabular grid  61  and occupies one row of the array. Each column of the array presents an attribute of the nodes and connectors. 
     Attributes of Nodes and Connectors: 
     Some attributes apply to both nodes and connectors. For example,
         (1) Unique identifying number   (2) Title   (3) Medium (e.g. audio, visual, text, HTML page, interactive graphic etc.)   (4) Type   (5) Link to Brief Abstract   (6) Link to medium   (7) Significance level   (8) Parent relationship to children corresponding to each appearance of the entity in displays and paths.       

     Other Attributes: 
     Other attributes apply to nodes or connectors but not both. For example, nodes may have a customized display. Connectors will have a unique directionality and identifying numbers for the nodes they link. In the primary sheet for the tabular grid  61 , all nodes and all connectors that are not path-dependent appear as rows in the tabular grid. The grid display is actually a hierarchical tree, with the rows and connectors as the highest level displayed by default. Any row corresponding to a node can be expanded to see all of its appearances in paths and custom displays, which appear as indented rows beneath. 
     Other Grid Instances: 
     Additional sheets can also be brought up as additional tabular grids  61  for any path and any custom display. The additional sheet shows only those nodes and connectors that participate in the custom display and/or path. 
     Joint Roles of Visual Display Field and Tabular Grid: 
     We now turn to a discussion of the uses of the visual display  60  and the tabular grid  61  in conjunction, to demonstrate their joint roles as core elements in the overlay builder  56 . 
     Early Stages of Developing Materials: 
     In the example below, the author makes use of the following elements in an intermediate stage of developing material for an electronic textbook:
         (1) the primary display field  60     (2) the primary tabular grid  61     (3) an additional tabular grid  61  workspace to handle irregularities in speech recognition   (4) an additional display area  60  with a structural display of the project matrix   (5) an additional display area  60  with a linear outline of topics   (6) an additional display area  60  with a dwordle   (7) an additional tabular grid  61  for topics   (8) an additional tabular grid  61  for connectors       

     Planning an Electronic Textbook: 
     Suppose that an author is composing an electronic textbook that offers text and image material for remedial, average, and advanced levels for a second grade mathematics class. The author also plans to include interactive graphics that offer more intuitive explanations of the topics. Consequently there are four “flavors” in the project: remedial, average, advanced and intuitive. The author is tentatively planning to cover about sixty topics, which might require up to 240 features if different features were provided for every flavor of topic. The author plans that the total will be substantially less, closer to 170, because for some topics one feature will serve both advanced and average, and for others one feature will serve for both remedial and average, and also because some interactive graphics features naturally handle more than one topic and present the logical connections between topics most clearly when topics are treated together in a single feature. 
     Importing Draft Materials Using the Tabular Grid: 
     The author has already used a word processor to create drafts of text for 80 features and a desktop publishing tool to create text and images for 40 more features. The author has also created 12 interactive graphic features that collectively present about forty topics. In addition, the author has 8 audio recording features that introduce and summarize eight sections of the subject matter. The author is now beginning to develop the electronic textbook. 
     The first step is to keyboard or import into the project database (such as the digital library  64  discussed above) the identifying information for these features: title, brief abstract, medium and type. All the titles, and some of the abstracts are pasted in from tables where they have been assembled. Media are straightforward and quickly specified. All are of type “feature”. The links to the media are pasted in at the same time. All of this work is done in the tabular grid  61 . 
     Creating a Concordance of Words and Phrases: 
     Upon request, the overlay builder  56  assembles a comprehensive concordance of all words and phrases in the features, with an associated database of all instances of each word or phrase used. Since transcriptions have not been provided for the audio recordings, the overlay builder  56  uses voice recognition to transcribe them, and a second tabular grid  61  worksheet is brought up to present queries arising from ambiguities in the transcription. In an embodiment, the word-recognition algorithm prioritizes its interpretations to emphasize terms already included in the concordance. The rows of the tabular grid contain successive segments from the transcription, and the author can either view only those segments containing highlighted queries or alternatively all segments in order, with the ability to step automatically from one query row to the next. 
     Display Field and Tabular Grid are Closely Coupled: 
     By default, primary display field  60  and primary tabular grid  61  are operating in lockstep; in other words they are fully coupled, so that each change made in either one is immediately reflected in the other. As a consequence, the display field  60  now displays icons for 140 features, arrayed in the order they were created. The author chooses to modify a display parameter so that feature titles are displayed in the display field  60 , instead of being latently available through tooltips. 
     Viewing Existing Titles in the Tabular Grid: 
     Now the author focuses on the titles of the 140 feature icons. This is the first time that the author has seen icons for the four different kinds of media together in a single workspace. The author is aware that some necessary features are still missing, that some features will serve for more than one stream (or path), that most of the intuitive interactive graphics cover more than one topic, and so on, but the full picture has not yet become clear. The author is not yet sure how many topics there should be, and is looking forward to improving clarity. 
     Opening a Structural “Project Matrix” in a Display Field: 
     The author sees that it is time to provide structure for these features, decides to go forward with a structured display, and opens another instance of the display field  60  for this purpose, beginning with the same display as in the primary display field  60 . This new structured display will be called the Project Matrix. The author defines two new structural attributes for the project: “stream”, with values average, advanced, remedial and intuitive; and “topic” with values that will be defined later. The “stream” attribute is used to identify those features that will eventually go into the average, advanced and remedial paths  12 ,  14 ,  16 , once they are placed in the proper order and connected. Since the author wants a traditional outline for the book, the attribute “topic” is associated with outline levels, which are specified as Title, Part, and Section. Each value of each structural attribute generates a structural node, so that there are now six structural nodes in the second display field  60 :
         (1) stream, with a parent relationship to its four children:
           i. average,   ii. advanced,   iii. remedial, and   iv. intuitive; and   
           (2) topic, a parent which is awaiting the creation of its children.       

     Laying Out the Columns: 
     The author positions stream in the upper-left hand corner of the display field  60 , and places advanced, average, remedial and intuitive in a row to the right. The author now lasso-selects the row, and chooses the menu option “Attribute order”, which assigns this sequence to the four values, and then chooses the menu option “Display as Columns” which sets a display parameter so that instances of each attribute will be grouped vertically in a column beneath its title. Five structural icons have now been positioned across the top of the second display field  60 . 
     Laying Out the Rows: 
     The author next places Topic in the upper left-hand corner, selects it, and chooses the menu option:” Display as Rows.” This causes the display field  60  to expect that values of Topic will be entered below, and it creates a blank space for this purpose. The author decides to create a rectilinear grid in this display field  60 , and selects this option from the Top-Level menu for the display field  60 . The display field  60  requests the widths of rows and heights of columns, and the author elects to select these by vertically and horizontally stretching or compressing grid heights and widths. Alternatively, height and width could be entered numerically. 
     Working Spontaneously: 
     Now the fun starts. The display field  60  is designed to facilitate spontaneous progress, and does not demand an orderly approach. Beginning from chaos—140 features in arbitrary order—and intending to reach about 170 features in perfect order, each exactly suited to its purpose, the author can start anywhere and tidy up whatever needs tidying, moving from point to point as interests and curiosity impel her or him. The author can be confident that the flexibility of the display field  60  will easily assimilate the fruits of this spontaneous approach without causing much extra work. 
     Assigning Feature A to both Average and Advanced: 
     For instance, suppose that yesterday the author worked on a text feature A that is well suited to handle both average and advanced streams for a topic part way through the pat. The author first drags the icon A with that title to the top position in the “Advanced” column, then right clicks on A and selects option “also applies”, and then drags the icon A to the “Average” column. Now the icon A extends graphically across both columns in the display field  60 . The display field  60  now shows that feature node A has stream attribute “advanced+average”. As yet feature A&#39;s topic attribute is void. 
     Creating Topic B which Applies to Feature A: 
     Considering feature A&#39;s title and perhaps reviewing its abstract and text, the author settles on a name B for the topic of feature A, right clicks on the grid rectangle in the topic column at the left of feature A&#39;s row, and when the entry widget comes up, types in the name for topic B. As a consequence, (i) the attribute topic now includes a value with that name B, which is a child of the attribute topic; (ii) a structural node B with title topic B is created and positioned in that grid cell; and (iii) the tabular grid  61  now shows the attribute topic B in the row for the feature node A. The author has now created one topic B, assigned topic B to feature A, and assigned feature A to both advanced and average streams. 
     What Next? Whatever Comes to Mind.: 
     What should the author do next? Respecting the power of subliminal thought, the author should do next whatever comes into her or his mind. For example, the author might repeat this procedure with another text feature that was recently worked on. Alternatively, the author might next focus on the remedial column for Topic B, and scan the titles of the other 139 features, seeing if one of them is a suitable fit. Or the author might choose to find other features that qualify for the advanced stream. Or the author might recall the intuitive interactive graphic C he or she earlier created, that applies to this topic and decide to examine it to see what other topics it contains. 
     Dwordling 4-Stage Intuitive Interactive Graphic C: 
     Let&#39;s suppose that the author next chooses to look at the intuitive interactive graphic C relevant to this topic and plays through the interactive sequence, focusing on what topics are covered. After pondering this, the author suspects that four topics are covered, of which the present topic is the third. To understand this more clearly, the author opens a new display field  60  window as a dwordle, and initiates an icon by typing in the name of node A in the entry widget at a spontaneously chosen place on the new display field  60 . The overlay builder  56  recognizes that the title applies to feature A, and creates here a second instance of feature A. The author could also have dragged and dropped feature A from the primary display field  60 , or dragged and dropped the row corresponding to feature A from the primary tabular grid  61 . Now the author replays the intuitive interactive graphic C and each time an idea comes up, pauses the play, spontaneously selects a location in the dwordle field, clicks, and types in there a spontaneous guess at the title and perhaps also abstract for an idea, creating an idea-icon. After the interactive graphic has been played, the author reviews the idea-icons in the dwordle field, contemplating them in their entirety with wide-angle focus. This calm viewing alone may be enough to bring to mind the titles for the three other topics covered. If not, the author can further contemplate the idea-icons in a relaxed way, remaining calm and alert, possibly moving the icons around into alternate positions and changing their titles to reflect partial understanding. If need be, the intuitive interactive graphic C can be played through again, continuing to enrich the contemplation. 
     Bringing in 4 More Topics: 
     Once the three new topic titles have become clear, the author concludes that these four topics do belong in sequential order in the linear outline for the text. The author can go back to the primary display field  60  and enter the three additional topics by placing the cursor above or below existing topic B and—with the proper keystroke—bring up an entry widget that will accept the keyboarded title and create the appropriate new structural nodes. Or the author can go to the primary tabular grid  61  and create three new rows and enter information for the new structural nodes. But suppose that while working on the dwordle, the author has already typed in the titles correctly and placed the four icons in the proper order (idea-icons in positions 1, 2 and 4, and the structural node A in position 3.) 
     Then the author has more refined and efficient procedures available. Working within the dwordle field, after first lasso-selecting the four, by placing the cursor on structural node A and using the proper keystroke and menu selection, the author can in two quick steps first transform the idea-icons into topics similar to topic B, and second assign their present positions as their ordering within attribute topic. Alternatively, the author can drag and drop the lasso-selected group onto node A in either the primary display field  60  or tabular grid  61 , and accomplish the same thing in a single step. 
     Using a Tabular Grid for Topics: 
     However, the author may also use a different approach, because after the work done so far the author may be ready to focus constructively on the topics in the linear outline. The author first opens another tabular grid  61  for attribute topic, and then drags and drops the lasso-selected list onto node A which is already displayed for that topic, and with the appropriate keystroke and menu selection, creates the definition and ordering of the four with a single click. The author will refer to this topic tabular grid  61  often, because it shows the structural attribute topic in a clear form suitable for contemplating and editing the overall linear outline for the electronic textbook. 
     Saving a Temporary Dwordle to Use as a Logic Display: 
     Note that the work with the dwordle display field  60  has served its immediate purpose. Four topics now have instances there. The author may choose to delete that display field  60 , but the author may also choose to save it for possible use in a logic display that documents Intuitive interactive graphic C. Next, the author returns to the primary display field  60  and drags and drops intuitive interactive graphic C onto the cell in column intuitive and row Topic A. Then the user control clicks the rest of the four topics to include them in the selection, and with the appropriate keystroke and menu selection “presents in sequence” records the fact that intuitive interactive graphic C presents the four topics in sequence. 
     Concentrating on the Project: 
     Let&#39;s review what has been accomplished so far. It may seem like a very small beginning—just two features out of 140 placed in the structural display, and only six cells out of perhaps 240 in the structural display filled by those features. However a sound basis for steady progress has been established. The author&#39;s subliminal thought is focused on the project, and visual analysis is now grounded in the views offered by the primary display field  60  and primary tabular grid  61 , the Project Matrix of topics and streams in the second display field  60 , and the Linear Outline in the second tabular grid  61 . Progress has been made and momentum is building. 
     Filtering Abstracts to Assign Attributes: 
     The author has already placed comments in the brief abstracts of some of the features identifying them as advanced or remedial. Moving to the primary display field  60 , the author filters for “advanced” in the Abstract column and finds  30  features. Reviewing the abstracts, the author is encouraged with their consistency. 25 of the features are worthy candidates for the advanced stream. When the author selects those 25 and filters for that selection in the display field  60 , the list of 25 also shows in the tabular grid  61 . Moving to the tabular grid  61 , the author enters the attribute advanced in their stream column and checks other attributes to see if anything needs tidying. The author tidies up the abstracts, removing the “advanced” notation and making a few editorial improvements. Then the author selects the 25 new advanced features and with the appropriate keystroke and menu selection causes them to be highlighted in the primary display field  60 . 
     Creating the Advanced Path in the Primary Display Field: 
     Returning to the primary display field  60  and noting the 25 highlighted features now placed in the advanced stream, the author next gets the features into their natural order of progression. The quickest, easiest and most useful way of doing this is to create an advanced path, and begin to fill it in it with these 25 new features plus the one already treated. The author brings up the Path control panel and creates paths for each of the four streams. Then the author activates the advanced path in the primary display field  60 , highlights nodes with stream attribute advanced, and contemplates the 26 existing highlighted titles. Building on prior work with their abstracts, the author can easily place them in order. He clicks on the first one to initialize the path and then clicks on subsequent ones in rapid succession with the appropriate key stroke to create connectors for the path sequence. About half way through and then again on completion, the author selects from the path control panel “display vertically” so the path nodes created thus far are shown in a vertical column in the primary display field  60 . 
     Repeating the Process for the Remedial Path: 
     Next the author repeats this process, this time filtering in the tabular grid  61  for “remedial”, reviewing the abstracts of the features found as displayed in the tabular grid  61 , assigning the stream attribute remedial to the qualified features, and editing the abstracts to remove the word “remedial” and tidy them up. Coming back to the primary display field  60 , the author activates the remedial path quickly and puts  30  remedial features into order on that path, again electing to display the path vertically. Now the advanced path appears on the left side of the primary display field  60  and the remedial path appears on the right side. Viewing the two paths in wide-angle vision, the author recognizes 9 cases where one advanced feature shares a common topic with one of the remedial features. Recognizing each pair helps the author to articulate the topic name, and when a name has been chosen, the author selects the pair, with appropriate click sequence and menu choice and types in the topic name only once to both create the topic and assign it to both features. 
     Now, returning to the second display field  60  “Project Matrix” with its structural display, the situation is much clearer. 13 topic rows now exist, and 20 individual features have been assigned to them, covering  24  cells: ten advanced, one average, nine remedial, and four intuitive. Also, 16 other features have been assigned to the advanced stream and 21 have been assigned to the remedial stream. 83 more features, however, have not yet been touched. 
     Putting Topics into Order: 
     As always the author has many choices for the next step, and will do well to let the decision emerge spontaneously. One frustration is that the order of the nine new topics has not yet been set. The features assigned to them have already received an ordering in the remedial path and the advanced path, and both of those orders are the same, but that order has not yet been applied to their topics. The author therefore uses the display field  60 &#39;s control panel to “order by path sequence” based on the advanced path. This creates 26 rows corresponding to the 26 items included in the advanced path. Ten of these have assigned topics, and the author selects those topics and the other three that were previously ordered, and as before assigns the order of their present positions to attribute topic. 
     Filling in the Gaps: 
     The author is encouraged by continuing success organizing the material, and also satisfied to find that the features prepared previously seem to be working well. The author accordingly takes on the task of locating existing features (from among the 101 not-yet-classified text features) that fit into average stream cells for the nine topics that have advanced and remedial features but no average feature assigned. The author is able to locate five by title alone, and two more by inspecting brief abstracts, making seven in all. Each of the seven is dragged and dropped into the appropriate cell with an appropriate click sequence to assign both the stream attribute average and the appropriate topic attribute. 
     Assimilating Audio Introductions for Parts of the Textbook: 
     Now that almost half of the existing features have been partly or fully categorized, the author decides that it is time to focus on improving the list of topics shown in the linear topic outline. A good way to begin is with the eight audio recordings intended to introduce and summarize parts of the electronic textbook. The author listens to them instead of reading their transcripts so as to more clearly sense how a user might experience them. The author listens to them first while looking at the “Project Matrix” display field  60  with the structured stream/topic display, noting down succinct points on a piece of paper (because keyboarding while listening would disturb the author&#39;s concentration). Then the author listens to them again while gazing with wide-angle vision on the Project Matrix: this is highly evocative. The author is able to place mentally six of the recordings as starting points for Parts of the text, and interpolates the names of these Parts into the existing list of topics. The author enters these Parts simply by clicking at the desired point in the topic column and using the proper keystroke sequence and menu selection to create a structural node with topic attribute Part and type its name into the text entry widget. The author then selects all instances of Part, and with the proper keystroke and menu sequence sets the default so that Parts apply on all streams and all paths. Consequently the cell for each stream in each Part row is now filled by that part&#39;s title. Next, the author drags and drops each of the six audio features to the Part that corresponds to them. The two audio features that were not yet used are given “under construction” tags that indicate what should be done with them, including such possibilities as “abandon” or “modify”. 
     Bringing in Features Along with Topics: 
     With these Parts in place, the author is able to quickly conceive of additional topic names that correspond to a number of existing features. As soon as a topic name is created it can be entered into the topic column at the appropriate position, and then the corresponding feature is dragged and dropped into the cell for the appropriate stream in that topic row, thereby assigning both title and topic to that feature. Soon there are 20 more topics placed in the appropriate order and 30 more existing features with assigned topics and streams. 
     Summing Up a Day&#39;s Work: 
     All this work has been, in a sense, bottom-up: the author is seeing things and making connections without imposing a rigid mental structure. Perhaps some topic names have been surprising, but they have been inserted anyway because they seemed to fit at the time. The emphasis has been on fitting features in rather than dealing with features that don&#39;t seem to fit in. All of the work described above may have been completed in the first day of work, and in the process the author has shaped an appropriate environment for the project and also attuned her or his subliminal mental abilities to both the working environment and the material. The present state remains chaotic, but there is now a firm foundation for the next steps. 
     Further Steps: 
     The author might establish any of the following projects to begin the following day:
         (i) Determine topics that relate to each intuitive interactive graphic, place these features in sequence, and create a path for the intuitive stream, intending to reconcile that path later on with the path provided by the textual material.   (ii) Focus on the linear outline, perhaps placing it into a display field  60  dwordle, and while looking at this with wide-angle vision from a top-down perspective consider what additional topics are needed, and in what order. As topics are added to the dwordle, they can be interpolated into the list of topics in their appropriate order, and viewed with wide-angle vision in the Project Matrix alongside existing feature titles, discovering both matches and subtle discordances suggesting that either a title or a topic needs to be enhanced.   (iii) Begin working at the level of the text attached to titles while viewing the display field  60 , to put together the average path in sequence, by activating path average and selecting individual pages one by one to extend the path, while reading the entire text of each feature carefully to see if something is missing that subtracts from continuity, so that issues can be noted down. For example, if a new node is needed, the author can create an average stream feature named “Needed: followed by the title”, with the details in its brief abstract and place that feature node in the path; if an existing feature needs to be improved, the author can place an under construction tag on it that describes what is required.   (iv) Work through the display field  60  Project Matrix topic by topic, carefully reading text and images for each stream defined so far and playing the intuitive interactive graphic mapped to that topic, looking for other existing features that might fill in any empty cell and seeing the material for that topic as a whole, so that issues come to mind or improvements suggest themselves.       

     Later Stages of Developing Materials 
     Creative Development in Open Context: 
     There is generally more than enough structure in a project at this point of development. When we work exclusively with conceptual thought, we often hold onto structure almost desperately, but when the wide-angle visual field contributes to the mental picture, structure receives surprisingly strong subliminal support, and conscious emphasis on conceptual structure can be relaxed. Let what appears like structure be present lightly, like a wisp of mist about to be blown aside. Nothing is yet settled, everything is open. In this spacious acceptance enough structure remains to suggest further developments. What can be redeployed? What new can be added? What old can be shifted to make a proper home for the items moved? Viewing in the primary path field  60 , view in depth the existing text and attributes of features in subliminally selected order. As you contemplate each one, visualize a layout for your features in the primary path field  60 —a non-linear outline—and consider where this feature might belong in the final perspective on the project? Drag it to that location, so that the perspective will gradually take shape. Whenever you feel ready to insert a title or specify further attributes for a feature, move to the primary tabular grid  61  and enter them there. 
     Drawing with Meanings: 
     Much new material remains to be created: 
     How can you discover what is already known but not yet consciously apparent? What will you find that is entirely unanticipated and yet ready to spring forth? How do you make a mental space into which subliminal knowledge can be projected? Just as an unfinished drawing invites lines into its white space, subliminally choose and subliminally place your meanings in the dwordle display field  60 , contemplate with wide-angle vision, and let new meanings present themselves appropriately. Open a tabular grid  61  connector sheet. As a new meaning presents itself, create an idea icon for it, and then drag and drop it into a new relationship pair in the connector sheet. Then consider what it relates to. Find a partner in a display field or tabular grid, and drag and drop that into the other side of the pair. When the context of a meaning becomes clear, begin typing text in the text entry tabular grid  61 . Let the words shape themselves successively, as you edit and extend with as little conscious intent as possible. 
     Visual Logic: 
     Here the term “logic” refers to reasoning and alternatively also to conventional association, or in other words, to any connection that can be explained in the context of your work. The term “visual” refers to making such connections visible. What are the logical connections among the items? How can they be understood? Which ones reinforce the linear order? Which ones violate it, either jumping ahead or reaching behind or just generally not fitting in at all? These are the connections that add sparkle to your understanding and help the user to see the bigger picture. It is easy to accommodate such anomalies in the non-linear outline. View the titles of the features in the project matrix display field  60 , and when a connection occurs to you, select the feature at one end of the connection, drag the connector to the other end to make the connection, and then shift to the tabular grid  61  connector sheet to enter attributes and descriptive text for the connection. As you&#39;re describing the connection it&#39;s often wise to work out the material carefully, taking time to get the reasoning exactly right or filling in the details of the association before moving on, because your thoughtful concentration on this connection may bring to mind other connections. 
     Multiple Display Fields and Tabular Grids can be Used Simultaneously: 
     Incidentally, don&#39;t worry about the many open display fields  60  and tabular grids  61  becoming inconsistent. They are all windows into the same database, and you can enter almost anything anywhere with perfect effect. The entry algorithms will handle most ambiguities and warn you if something specific needs to be entered in the primary display field  60  or primary tabular grid  61  to clarify your work. 
     Developing the Overlay: 
     What has been covered above concerns developing original source material. That can be thought of as the first stage of preparation. Of course this first stage does not apply when placing an overlay on other people&#39;s material. The second stage in a broad sense consists in developing your overlay for your or other people&#39;s material. This is closely analogous to the work that someone else would do if they were making the overlay on your material, but it is a much richer in options and potential innovation when you do it yourself, because as the overlay develops you can improve your material through new insights or dovetail your material to fit better with the needs of navigation. There is another very positive aspect to developing your own overlay: you may now be able to redeploy as optional features some of the material you abandoned earlier. 
     The Non-Linear Outline Blends Language and Diagram: 
     Here are some ideas that may help you to appreciate the potential of this new way of working: The non-linear outline in the form of an overlay blends two ancient skills: languages and drawings/maps/diagrams. These two skills, in turn, depend on two distinct capabilities of mind: verbal and visual analysis. The rigidly linear form of a printed book is rooted in the memorization and subsequent recitation of spoken words. Both the shift to an electronic textbook with its non-linear outline in an overlay and the move away from linear page sequence to a collection of information lessen the predominance of verbal analysis and move us toward a closer balance with visual analysis. This shift can enhance our ability to handle complex matters, for two reasons: first, verbal and visual analysis can enhance one another; second, the visual field is the superior tool for assimilating and comprehending many factors that are simultaneously present. Visual analysis takes us almost effortlessly to the big picture. The implications for the use of our mind are quite profound. It is not surprising that new tools will help us to perform well in this new environment and that our mental habits may change for the better as a result, allowing us to think more productively. 
     Views and Perspectives: 
     Moving on to discussion of procedure, developing an overlay is discussed in detail above. Here we add further detail about various additional views (i.e. perspectives) that serve the needs of both users and authors, such as the structured view utilized in the “Project Matrix” presented above. 
     Creator&#39;s View: 
     The function of Creator&#39;s View is to preserve the creative process, allowing the author to preserve and revisit work in progress. This view is a selective snapshot of the displays (e.g. the content of the display field  60  and/or tabular grid  61 ) that you deem relevant at a point in time. Ordinarily these are archived for the author to return when necessary. 
     Structural Views: 
     A “structural” relationship is an orderly relationship that extends across many features. It is a type of logical relationship that can be accommodated by an orderly display such as parallel paths or a rectangular table with rows and columns. 
     To offer a few examples, if a series of textbooks in English cover similar grammar topics in similar order in successive grades, the rows would be topics and the columns would be grades. This view allows the user to see how the topics develop from grade to grade. If the chapters of a textbook regularly offer text, examples and exercises, the rows could be chapters and the three columns could be text, examples and exercises. If the textbook covers the same material at average, remedial and advanced levels, the rows could be topics and the columns could be remedial, average and advanced. If a history text offers chapters that consistently cover such themes as social, political, legal and economic events in successive periods, those periods would be rows and the themes would be columns. 
     The author identifies rows and columns either by attribute, or by path or by both attribute and path. The overlay builder  56  displays structural material in useful ways: 
     In the display field  60 , rows can be identified by horizontal alignment of features, and columns can be identified by both vertical alignment of features and by highlighting, so that the columns appear as highlighted vertical lines and the rows show up as horizontal alignment of features in these lines. Labels for rows and columns can be provided in the margins of the display or within the body of the display. 
     The display field  60  positions all features that are not part of the structure in close proximity to the structural elements they connect with, and these non-structural features can optionally either be shown or become invisible. Features that are shared between multiple rows or across multiple columns are handled by placing the feature in a central position and highlighted aliases in the other positions. 
     In the tabular display  61 , the rows and columns can appear as in a spreadsheet, with highlighted columns and labels in the margins. Non-structural features are handled analogously to the display field  60 , by placing them proximately in interpolated rows and columns that can be optionally hidden. Shared structural features are handled similarly to the display field  60  by highlighted aliases. 
     Path Display: PathText Ordering: 
     When a path is displayed or printed as ordinary text, the title and text attributes of both nodes and connectors are presented in their appropriate sequence. This sequential ordering is another option for structural display, called “PathText”. In PathText material can appear sequentially one row at a time or one column at a time, thus grouping the material either by row or column, and labels can be optionally interpolated into the text showing the row and column at the head of each section. Non-structural features are handled by placing a connector in the text wherever a connection occurs, and shared structural features are handled optionally either by interpolated aliases or by highlighted connectors in the aliased positions. 
     Using Structured Displays during Development: 
     It can very helpful during the development process to bring related materials into the wide-angle visual field simultaneously or successively: 
     Mistakes are picked up easily, inconsistencies present themselves for resolution, possible improvements become readily apparent and new ideas are stimulated. When the materials are related though a logical structure, the benefit is even greater and significant insights may arise. If the author plans any structured displays for the final product, these can be assembled early in the development process and the author may review them periodically to move the project forward and monitor progress along the way. The author can also create temporary “tracking displays” to view material under development by assigning temporary attributes as needed and formatting a structural display based on those attributes. 
     Structured Displays in the Final Product 
     Complex presentations in many fields may benefit from regular structure within chapters or across parts of a book. The structure underlies the presentation and helps to organize and clarify the material for a user. Whenever such structure is present, the table of contents or non-linear outline can be rendered as a structured display. When topics are structured, a gallery node reflecting the topics available to visit can take the form of a structured display. When information is structured within a topic, a structured display can appear in the text displayed at a given node. Structure also results whenever the author systematically prepares alternate styles of presentation: 
     For example, if a textbook covers the same material in both procedural and intuitively meaningful forms, as discussed earlier, these could be the two columns in a structured display that might be quite helpful to students. 
     Structure in an Arranged Display: 
     If a textbook offers two parallel paths, one for the student user and one a “teacher&#39;s guide” for the instructor or parent, these two paths can be arranged so as to appear side-by-side to the instructor or parent as highlighted columns in the display area  60 . The parent or instructor can also arrange whether or not the student can see their teacher&#39;s guide column, and if so which material in that column will be shown to the student and which material (such as answers to test-your-skills questions) will be hidden (or alternatively displayed only after each test was completed and the student&#39;s performance recorded). 
     Glossary View and Instance View: 
     Using the glossary in the overlay builder  56  is much like an ordinary glossary. When you click on a term in the text that appears in the glossary the glossary entry appears. However it has two key enhancements:
         (i) The glossary in the overlay builder  56  knows the specific text from which you came, because it records that as part of recording your traversal through the textbook or overlay. Its display takes that into account to customize the information that you see.   (ii) All instances of the term are linked into the glossary entry, and the glossary display shows the total count of instances. You can elect to view all those instances in alternate forms of Instance View:       

     Displayed successively as text extracts that can be optionally expanded when you wish to see the entire surrounding text; shown by highlighting features and connectors in the display area  60 ; or shown as icons in a gallery. In all three cases, the original location from which you came is highlighted in the display area  60 . 
     Viewing the Instances of a Glossary Term: 
     A glossary will probably help you during your work, and will almost certainly help your readers. Each term in the glossary is briefly defined and put into context. Uses of the term are automatically linked to the glossary, so that you and your users can optionally begin from any glossary item and bring up a gallery that presents all the instances of the term. This can help you to check the consistency of your usage. 
     Viewing Instances of a Term not in the Glossary: 
     When a user elects to search for any term or phrase, the list of instances will be created and Instance View can be entered at that time to activate any format of Instance View, even though the term is not in the glossary. 
     Benefits of Instance View During Development: 
     During development, glossary Instance View in text form can help you to check the consistency of your usage, and the visual display form can help you to tidy up your presentation and check the validity of connections you have made by verifying that the term appears where you intend it to. Searches for terms not in the glossary will count the instances and map appearances, so that you can decide whether the term should be added to the glossary and consider how best to describe it. 
     Activating Instance View: 
     The glossary can be accessed by clicking any glossary term. Instance View can be activated for that term from Glossary View, and can be activated for any other term or phrase by searching for the term. Whenever an arrangement of the material makes a feature or connector invisible, instances of terms in that section disappear from Instance View. 
     Accessing Underlying Content Associated with Nodes: 
     The overlay builder  56  also displays the underlying content associated with the various nodes and connections of the overlay  41  or electronic textbook  5 . In one example, the overlay builder  56  interfaces with an application used to store the underlying content. For example, the overlay builder  56  interfaces with a word processor, browser or document display software such as a Portable Document Format (PDF) viewer, to display textual content natively. The overlay builder  56  interfaces with audio playback software installed on the user&#39;s computer to play audio content, and with video playback software to play video content. In an example, the audio and video playback software is integrated with the user&#39;s browser. Alternatively, the overlay builder  56  can display content using its own integrated capabilities. For example, if the user creates a comment, that comment can be stored by the overlay builder  56  in a proprietary file format associated with the overlay builder, and then displayed by the overlay builder  56  in a separate window  64 , or a pop-up window of the overlay builder  56 . The underlying content may similarly be displayed. 
     Aids to Productive Thought 
     Using Visual Display to Coordinate Visual and Verbal Thought: 
     The visual display  60  of the overlay builder  56  is also used, in an embodiment, by authors of overlays  41  or electronic textbooks  5 , as a tool to aid the author in construction the overlay or electronic textbook. In order to better develop new ideas for inclusion into the nodes and connections of the overlays and electronic books of embodiments of the invention, an author can use the display area  60  of the overlay builder  56  to identify candidates for the nodes of the overlay, and then identify connections to be made between the nodes of the overlay. 
     The Dwordle: 
     In an embodiment, these candidates are identified by constructing “dwordles,” using a selection from an inventory of terms in the content used by the overlay builder  56 . As discussed in further detail below, a “dwordle” is a word or phrase, randomly selected and randomly placed in a visual field. For example, where the overlay builder  56  connects to a digital library  54  containing content  52 , an inventory of terms in the content  52  is presented to the author by the overlay builder  56 . This inventory of terms may be in the form of a list, or a collection of nodes labeled with the terms. The terms may preferably be single words or short phrases, but may alternatively be longer texts such as sentences or paragraphs. Where the overlay builder  56  (or add-on  40 ) connects to pages  34  available over a network  38 , the inventory of terms may be constructed by scraping, or otherwise collecting a list of terms from the pages  34 . Similarly, when the overlay builder  56  is used to construct the electronic textbook  5 , the overlay builder  56  will draw on the content used to construct the electronic textbook  5 , which is in an embodiment, content stored in the digital library  54 , or accessible over network  38 . Alternatively that content is available from the computer  32 . Additional terms in the inventory of terms may be supplied by the author. The author may add terms spontaneously, by typing them into an entry widget in the display field  60 . Spontaneously added terms are retained in a holding buffer for potential later inclusion in the inventory of terms. 
     Subliminal (Seemingly Random) Selection and Placement: 
     The author randomly selects a term from the inventory as a dwordle, and randomly places that dwordle in the display field  60 . Or the author spontaneously thinks of a new term, randomly selects a location in the display field  60 , clicks there to bring up an entry widget, and types in the new term for entry at that location. The author then randomly selects additional terms, and manipulates them as discussed in further detail below, to identify connections between them. In the earlier stages of composing the material, the author&#39;s work with dwordles helps to develop material, bringing forth conscious insights that might otherwise arise much later or might never take shape at all. Later in the editorial process, these dwordle connections aid the author in identifying relevant connections to use in crafting the overlay or electronic book. Once the author has completed the dwordling process, as discussed in further detail below, then the dwordled terms are used by the author to evaluate and consider connections to make between nodes containing content that includes the dwordle. For example, if the author perceives a connection between a first term found in a first content item  52 , and a second term found in a second content item  52 , then the author can consider whether it would be appropriate to include the first content item  52  and second content item  52  as nodes in the overlay  41 , and the connection between the terms as a connection between the first content item  52  and the second content item  52  in the overlay  41 . Because the overlay builder  56  includes the visual display  60  and has available a term inventory, the author is able to easily draw from the entire relevant inventory of terms to populate dwordles, and is also able to easily render connections between terms and translate those terms and connections into nodes and connections of the overlay  41 . 
     The Dwordle in Context: 
     Dwordles are one example of an aid to productive thought, in accordance with embodiments of the invention. To further understand what dwordles are and how they aid in creating the overlays  41 , it is helpful to consider the following discussion of aids to productive thought, including the interaction between the verbal and visual fields of focus, and visual and verbal analysis frameworks, and the use of dwordles. 
     Burgeoning Conceptual Complexity: 
     Our modern world is knowledge-based but conceptually educated. Our interactions are relatively harmonious when compared to past history, but as a result of telecommunication and the Internet, our interactions are conceptually mediated to an unprecedented degree. As a result we are becoming increasing distanced from one another and even estranged from our own nature. The complexity implicit in cultural mastery is burgeoning at the same time that the elements of our culture are increasingly perfused with concepts, and the universal education that helps us to keep up with all these concepts tends to cut us off from our heartfelt humanity. 
     The scientific endeavor, with its roots in disciplined and unbiased observation and verifiable prediction, its emphasis on rigorous analysis, and its active engagement in continuing enhancement, is a wonderful basis for humanity&#39;s continuing growth. However, it too is conceptually based and stretched to its limits by the complexity of natural and human systems. 
     Conceptual thought can be verbal or visual or emotional. (It&#39;s relevant that our culture&#39;s verbal emphasis may have increased during the first five decades of computer availability to a peak in the 1990&#39;s, and the proliferation of images on the web may now have begun a corrective trend back into balance with visual expression.) 
     Coordinating Conceptual Thought with the Visual Field: 
     Three factors make it beneficial to open up conceptual thought to coordination with the visual field: overemphasis of verbal thought; the comparative advantage of the visual field in handling complexity; and the risk that web-based learning may lead to mere information rather than knowledge. 
     The APT initiative is a practical one: tools for productive thought will succeed and meet their goals if they yield more satisfactory results for their users. 
     Knowledge is Information in Proper Context: 
     Mere information is data out of context. Without context, you do not know what to use data for and how to use it appropriately. Searching on the Internet you may find that you have gained information but still lack the knowledge you need to use the information effectively to satisfy your purposes. Information becomes knowledge when you know how it should play a role in your life and know how to make use of it. 
     To make wise choices or decisions, you need to know your own circumstances, the possibilities available, the principles or criteria for appropriate choice and how the various possibilities accord with these considerations. It is good to learn to bring all these factors consciously into your mind when making a choice, because conscious attention will help to balance various considerations and weigh their importance. There is no need to go about this abstractly by telling yourself how to think. A few well-designed questions will put you in the proper frame of mind. When you are making choices and the choices are well informed, you are creating a context that will frame the information you learn as knowledge rather than filing it as mere information. 
     Conscious Thought and Subliminal Thought: 
     In seeking a conclusion, for example to solve a problem or to learn about a particular subject matter, it is helpful sometimes to give purposeful thought to the problem. That is, to think something through, setting in motion a train of thoughts that continues until a successful conclusion is reached. Doesn&#39;t it feel good when you begin with no understanding or misunderstanding and eventually reach clarity? This is a form of productive thought. Once you recognize productive thought in your own experience, you have a basis for gradually reshaping your thinking so that more and more of your conscious thought is productive. 
     It&#39;s helpful to note, however, that most of your useful mental functions are performed subliminally without conscious awareness. When you catch a ball, you may think “I am catching this ball,” but everything that your body does in order to catch it is being calculated and performed subliminally. Likewise, when you think “I have a new idea,” most of the mental functionality that brought forth the idea was subliminal. 
     It&#39;s helpful to think of the mind as including both subliminal and conscious thought. When you reflect on this you&#39;ll find—perhaps to your surprise—that much of your conscious thought is actually getting in the way of productive thought and preventing useful productive ideas from reaching your conscious awareness. 
     This insight suggests that it might often be better to let your conscious thoughts fade into silence instead of letting them run along in their usual way. Pragmatically, we&#39;re looking for whatever form of conscious thought will best support broad minding (the mind as a whole) in productive thinking: when that means silence, there should be silence. 
     Minimizing Distortions Due to Emotions: 
     We&#39;re all familiar with emotional factors like writer&#39;s block, procrastination, infatuation, discouragement, and magical or wishful thinking in others and in ourselves. Emotions are closely linked to conscious conceptual thought and can obstruct, confuse and bias your thought process. In general, alert concentration and relaxation can soften these effects. Attending to the wide-angle visual field promotes alert concentration and engenders relaxation, which can be very helpful. Beyond that, the melding of graphic and verbal meanings in embodiments of the invention as discussed above often promotes alert concentration. As we become more interested in our work and begin to make real progress, the emotional effects usually subside. 
     Benefits of Introspection: 
     Introspection, literally examining inwardly, can be very helpful when engaged for a productive purpose. When you introspect with the intent of developing more effective and reliable ways of thinking, you can make important discoveries that take you to new ways of thought. These are truly discoveries, for two reasons: first because they concern your own mind, which is yours alone to explore, and second because you discern some things that go against views about mind that are prevalent in our culture. 
     Limitations of Conscious Thought: 
     It is helpful to productive thought to coordinate conscious thought and subliminal mental activity. The brain activates more than 100,000,000,000,000 calculations a second. Conscious verbal thought achieves about two words a second. Needless to say, there is a bandwidth mismatch. You will never be able to bring even a miniscule fraction of the brain&#39;s calculations into conscious thought, but it is beneficial to make space for subliminal mental activities to work alongside the conscious thought process and contribute knowledge and insights. Both conscious conceptual thought and subliminal mental activity contribute to the thought process, and it makes sense to coordinate them to attain our purposes. 
     It&#39;s helpful to develop habits of thought that make space for creative thoughts to surface. It&#39;s helpful to accept the value of subliminal mental activity in dealing with complexity. In the same way that we cooperate with a computer, it&#39;s helpful to cooperate or coordinate conscious conceptual thought with broader mental activity. 
     Conscious Verbal Thought and the Wide-Angle Visual Field: 
     Conscious verbal thought is linear. It traces one meaning, one connection at a time. It is useful for finding errors and getting things right. As it traces a single sequence of meanings, verbal thought is like listening or speaking. Thinking in images sometimes serves a similar function, exploring and tracing connections. 
     Unlike listening to speech, the human visual field takes in many things simultaneously. When we relax our gaze and rest in wide-angle vision, the visual field supports wide-reaching awareness. (By contrast, when we focus acutely and narrowly, the visual field supports intense analysis. Relaxed and soft, the restful gaze of wide-angle vision is an ideal complement to the linearity of conscious verbal thought. This restful gaze can be almost entirely free from emotional bias, and naturally attends to everything in sight, treating everything equally and allowing us to see things that do not fit into our preconceptions. 
     Benefits of the Dwordle: 
     Many elements of embodiments of the invention discussed above individually and jointly help to bring the benefits of both acute visual focus and wide-angle gaze to the thought process. 
     A unique element of embodiments of the invention, the “dwordle,” helps you with both aspects of coordination: coordinating conscious thought with subliminal minding, and coordinating verbal analysis with the wide-angle visual field. The “dwordle” teaches you to activate wide-angle visual awareness and derive direct benefit from subliminal broader minding. The dwordle accomplishes this by completing a feedback loop between verbal conceptual thought and the visual field. 
     Visual Focus: Acute and Wide-Angle: 
     Human vision has two different styles of focus. These derive from physical features of the eye and the connections of the optic nerve to the brain. “Acute focus” is sharp vision provided by the center of the retina (the “fovea”), and “wide-angle focus” is less acute vision provided by the retina as a whole including that central region. These are rooted in physical properties of the eye and nervous system, and they also correlate with our mood and sense of identity. 
     We can use these contrasting forms of mental activity in several exercises, and it is helpful to appreciate them. Modern life may tilt us toward habitual acute focus, making it difficult for us to deliberately relax into wide-angle focus. If a person has lost discretionary access to wide-angle focus, it is particularly important to regain this because wide-angle focus is an influential resource with profound impact on mental activity: 
     Wide-angle focus opens the field of attention, whereas acute focus narrows it. 
     Acute focus, which has also been called “hard focus” benefits from the dense visual receptors in the fovea and the many nerve fibers that connect the fovea to the visual cortex. Humans naturally focus their eyes more sharply to rely on this central region of the retina when they want greater visual detail or when they want to analyze what they see. With this kind of focus, eye and brain are closely coupled for analytical and decision-making purposes. When humans are intensely interested in something they naturally use acute focus. 
     The other focus has been called a “soft focus.” Here the eyes are relaxed and a much greater area of the retina is called upon. When humans use wide-angle focus the whole field of vision is warmly alive. The feeling is gentle, somewhat like meditation. Humans use wide-angle focus when peripheral vision is important, because peripheral vision requires the outer region of the retina. This is why we refer to it as “wide-angle.” 
     The most light-sensitive receptors in the eyes are in the outer regions of the retina, and humans need to use wide-angle focus when walking in the darkness or looking at the night sky. If a person goes out and night and sees few stars, even after waiting for a minute or two for his or her eyes to adapt to the dark, and a little later sees many stars, the change has resulted from a shift from acute to wide-angle visual focus. 
     The “depth of field” in human vision is much greater in wide-angle focus. When a person wants to see clearly objects that are close and objects that are distant at the same time, the person uses wide-angle focus. With wide-angle focus, images are equally sharp at all distances. Designers of tranquil gardens such as the gardens in Japan invite visitors to increase the depth of field in order to calm the visitor, precisely because it invokes the visual state of wide-angle focus. When significant objects are present in the foreground, middle ground and background of a person&#39;s vision, the person naturally shifts to wide-angle focus in order to attain depth of field, and as a result the person&#39;s eyes and spirit relax. 
     Becoming Familiar with Wide-Angle Focus: 
     We have discussed four factors that induce wide-angle focus: peripheral vision, relaxation, darkness, and visual acuity at a range of distances. Peripheral vision is perhaps the easiest tool with which to explore wide-angle focus. Here is an exercise: Extend your arms in front of you with your hands at the level of your eyes. Focus on your hands, and keep them at eye level as you slowly swing your extended arms outward to the side. 
     As your hands swing backward and approach the edges of your visual field, they are picked up by peripheral vision and you are seeing in wide-angle focus. Continue to focus on your hands and move them as far backwards as you can without losing sight of them. Then keep your hands in view to sustain wide-angle focus as you attend to the entire visual field. See if you can relax and enjoy this feeling of softness. 
     Once wide-angle focus has stabilized, you can put your arms down if you want. Begin to play with the qualities of the softly-focused image. Very slowly move your eyes from side to side and up and down. You should find that your entire visual field is stable during this movement: there is no break in attention, just an extension. You see a single comprehensive image: as your eyes move to the left the image extends in that direction, and likewise up or down or to the right. As it extends your visual field retains the memory of the opposite sides of the field: the image is stable beyond the range of any one gaze, and when you later bring your eyes back where they were before, the lost part of the image comes back as if it has never changed and has been waiting for you. Though your eyes and gaze have moved, you have not diverted your attention at all. 
     Contrasting Wide-Angle and Acute Focus: 
     Another way to explore wide-angle focus is to focus on something complex and nearby like a messy desk or a loaded dinner table while moving your hand through the air between your eyes and the objects in your field of vision. If you are in wide-angle focus the background remains stable while your moving hand occludes various parts of it without disturbing the complex image. You can use this technique to recover wide-angle focus at any time during the day. 
     By contrast, with acute focus attention is intensely focused at the center of the visual field. Attention moves with the eyes. The image reforms wherever your eyes move. When you move your eyes in acute focus, it is as if your gaze is darting from one target to the next. There is a break in attention. Apparently the break occurs both in mind and eyes, for it distracts from engaging in complex physical activities like driving a car. At first vision is centered at one location, then it refocuses somewhere else and the area in between is blurred during the transition. The new target to which your gaze darts comes into focus almost instantly, but you may be able to sense that the image surrounding your new point of focus shapes itself more slowly than the target and remains blurry or vague for a short while. 
     Verbal and Visual Analysis: 
     Related to the ideas of acute and wide-angle focus, are the ideas of verbal and visual analysis. Humans can easily access two basic analytical frameworks: verbal analysis that supports hearing, speech and communication, and visual analysis that supports vision, spatial relationship, and engaging in physical activities like athletics or conversing or driving a car in physical time. When these two frameworks are allowed to interact, they cooperate well: the combination of the two is better than either one used separately. We can use a lightweight tool, the “dwordle”, in conjunction with the principles of acute and wide-angle focus above, to enhance their cooperation. 
     Using the dwordle we are able to sense the respective strengths and limitations of the two frameworks and allow them to work together. This mind training takes form in conscious experience, enhancing the effectiveness of productive thought. As the human mind is trained to adopt this new technique, it learns to deploy it in its broader minding. Ultimately broad minding may take over these capabilities so fully that we receive the benefits almost instantly without needing to go through a conscious process to achieve the results. 
     Visual images and verbal concepts are both important in conceptual thought, as evidenced by the fact that each plays an important role in the flow of conscious meaning-laden thoughts. Vision receives many stimuli simultaneously: in any moment, some objects in the image are changing, some are moving, and some are fixed. Verbal information arrives in one sole sequence: newly arriving information is appended to a remembered sequence of sounds, and the sequence extends as time passes like a line being traced. The differences between the information sets require different forms of processing, and give rise to different styles of analysis. 
     The visual field specializes in receiving simultaneous stimuli and placing them into a spatial context, while verbal thought specializes in encoding and decoding meanings and linking them to related meanings. These different specializations naturally complement one another. 
     Verbal Analysis: 
     Language and formal thought, and the mental structures that support them, are important resources for pondering and creativity. Formal thought depends on reference and so relies on previously formed labels and references or associations. We can refer to these verbal labels as “words” and “meanings”, with the understanding that these terms include such things as numbers and arithmetic. The analytical use of words and meanings can be termed “verbal analysis”. The words and meanings of conventional language and principles of formal thought such as grammar and arithmetic are a toolkit for reasoned analysis. 
     This toolkit is very convenient when working within the range of words and meanings that come packaged within conventional language. Specialized vocabularies are invented to apply logical reasoning to fields ranging from architecture through mathematics to zoology. Formal thought is a natural basis for exploring conventional wisdom already embodied in formal thought. Inconsistencies and new connections can be discovered. Subtle implications can be inferred. 
     As new insights and implications emerge, new words and meanings can be developed to extend conventional wisdom. The process continues indefinitely. 
     Limitations of Verbal Analysis: 
     However, verbal analysis faces multiple handicaps when the purpose involves new perspectives and creativity. The strengths of verbal analysis bring corresponding limitations, as explained in the following paragraphs. 
     Verbal analysis depends on packaging into conceptual constructs for its broad reach—a great strength. However packaging often conceals the packaged contents, cutting off access to the experiential knowledge to which the packaged meanings refer. Analytical use of packaged constructs tends to intensify the difficulties of opening packages. When content is essential to creativity, as is usually the case because packaged constructs do not capture the potential of the knowledge they refer to, we can easily get stuck with no way forward. 
     The meaningful connections of verbal analysis are subtle and refined and offer unlimited abstraction—a great strength. However verbal analysis tends to take the correctness of these connections for granted, and rarely takes the time to unpack the connections to validate them through broader minding. Once in place and incorporated in analysis, even a gravely faulty connection is unlikely to be detected unless it raises contradictions. Verbal analysis is weak in detecting its internal errors and therefore vulnerable to error. 
     Language is central to communication—a great strength. At every point along the way, whether clearly established or veiled by confusion, we can describe where we are. However, the emphasis on communicability actively inhibits the initial stages of the deeper forms of creativity, because whatever is newly unfolding will not yet fit in. Formal thought demands milestones along the way and tends to inhibit creative exploration. 
     Because of its role in communication, language is central to the social model—a great strength. This applies especially to conscious conceptual thought, which is prominent in inward display of relationship models. Conscious conceptual thought can easily become entangled with emotionality and self-image. These are important ingredients of the social model, and so are highly relevant for creativity within the context of the social model. However, within the context of productive thought, these collateral effects are detrimental. Emotional entanglements and presentations of self-image are sure to cause distractions and likely to impede progress. 
     Because of the importance of communication, we have learned to concentrate intensely on formal thought. Our mind can simultaneously focus on conscious conceptual thought and activate relevant links to other concepts not presented consciously—a great strength. However, this intense concentration tends to cut off access to other aspects of subliminal minding. This is a major weakness, because we are often unable to take advantage of broader mental capabilities that we are in need of. 
     Because of the linear character of sound, which is expressed sequentially over time, expressed verbal meanings are linear. Broad minding skillfully expands the linear elements of verbal analysis into a network of interconnecting connections that mutually support one another, effectively traversing many links of a network at once—a great strength. However, only one connection can be played in consciousness at any one time, so conscious verbal conceptual thought is intrinsically linear. Even when conceptual thought is expressed in conscious images rather than words, the linearity tends to persist. Navigating a complex multi-layered linear network one connection at a time is slow: much, much slower than broad minding. By the time we come to the end of a conscious thought, mind will already have moved on. As a result, there is inevitable discordance between conscious conceptual thought and broader mental capabilities. There is tension in this discord, and effort is required to maintain it. We lose access to beneficial aspects of subliminal minding that would be available in a more relaxed state. 
     Each successive thought narrows our focus onto its topic and supports this with relevant local connections—a great strength. However, as we localize in this way it is hard to maintain a consistent broad focus, and it is likely that we will sometimes lose track of the big picture. Moreover, once a connection is activated by projection into conscious thought, its priority is increased and mind tends to return to it, so conscious conceptual thought tends to be repetitive. Because of the combined effects of losing track of the big picture and tending toward repetition, we often find ourselves following a worthless track again and again, repeatedly presenting a broken train of thought and hardening our perspective until creativity becomes nearly impossible. 
     Because of these limitations of verbal analysis, it is important to supplement it with other styles of analysis that can work around these challenges. This way we can combine the strengths of multiple styles and minimize the costs of their limitations. Visual analysis naturally overcomes many of these limitations. 
     Visual Analysis: 
     The visual field presents a rich array of forms arranged in three dimensions. Tremendous mental calculations are required to present these in a timely way. The field distinguishes among changing elements, moving elements and fixed elements and handles them in different ways. Changing elements are noticed, processed, and recognized. Moving elements are carried forward with their prior assigned recognitions. Fixed elements continue in place as previously recognized. 
     All of the elements are presented for analysis simultaneously, as a single present array. Elements recognized some time ago are arranged alongside others newly arrived. Elements&#39; status as fixed, moving, or changed is provided, and elements with common features are linked to one another. Patterns and textures, colors and shapes are identified. Spatial relationship in three dimensions is readily available, and provides context within the scene. The entire scene is easily scanned for any object. The context is powerful and supports memory, analysis and planning. 
     Visual analysis identifies the elements of the scene and studies relationships among them. Using a longer time history for perspective, motions are analyzed and rhythmic patterns such as the swinging of a pendulum are detected. Movement is modeled and changes are analyzed. All of this is done very quickly to keep up with physical time. 
     Limitations of Visual Analysis: 
     As with verbal analysis, the strengths of visual analysis bring limitations along with them. Visual analysis handles a vast amount of timely data very quickly—a great strength. However, when it comes to pondering meanings and searching for abstract relationships, the visual system seems to be a tool of the process rather than the manager of the process. 
     Visual analysis has wonderfully quick access to long-lasting memory that supports recognizing faces and places and objects and symbols—a great strength. It seems that these memories are closely linked to vision and accessible through visual analysis. However, it is not clear that the visual system has direct access to the general class of meaningful associations that are the specialty of verbal analysis. For example, when a newly appearing object is unexpected and difficult to recognize, visual analysis gives way to broader minding and we can sense the delay and dislocation of experience as attention shifts to other mental resources to resolve the mystery. 
     Visual analysis elegantly handles spatial relationships in three dimensions—a great strength. It can also detect relationships among elements in scattered locations that share a visual feature such as movement, change, or color. However, attributes of relationships must be represented symbolically, as for instance by an arrow in a diagram, to present them to the visual field. Visual analysis cannot itself overlay the nature of connections, and relies on formal thought applied to recognized images for this. 
     Visual analysis is central to the calculations that support engaging in physical activities in physical time—a great strength. However, it works best with continuously acting causes that exert incremental effects. It does not respond well to discontinuous, latent, or multi-factorial causes and relationships. 
     The visual field brings in every aspect of the visual array with equal status—a great strength. It can be easily prioritized to search in this extensive array for something that moves, emphasizing motion; or a green object, emphasizing color; or a pencil, emphasizing shape; or something that glints, emphasizing brightness; or something that sparkles, emphasizing change. After a skill like reading has been developed, visual analysis can be trained to search for a familiar symbolic form such as a letter in this extensive array. Thus visual recognition and search work well with visual cues and symbols. However, the visual system does not seem to handle abstract meaning in a native way. Instead, it passes on questions of meaning to broader minding quickly and efficiently. 
     Visual-Verbal Interchange: 
     Visual and verbal analysis are complementary systems. For example, verbal analysis focuses on a single sequence, while visual analysis sees a complete field. Verbal analysis works with labels, while visual analysis works with direct experience. Verbal analysis accesses formal thought and formal knowledge, while visual analysis recognizes images through matches between direct experience and recorded direct experience. Verbal analysis is locally focused with an abstractly connected proximate network, while visual analysis is broadly responsive, and when in wide-angle focus, grants equal value to everything in the visual field. Verbal analysis takes time, and conscious verbal analysis is ponderous, while visual analysis is quick. 
     When they are coordinated the strengths of the two can be combined. We rely on verbal analysis to support visual analysis. For example, visual analysis accomplishes recognition of a face or place on its own, and makes the recognized images available to verbal analysis to convey labeling and packaging to the networks of formal thought. For our mind to function as well as it does, the channel from the visual system to the verbal one must operate very quickly. 
     To cite one instance, training systems for “speed reading” have been available for many years. These rely on the wide-angle focus of the full visual field, rather than the acute focus employed for ordinary linear reading, to achieve reading speeds of thousands of words per minute. This pace is so much faster than speech or verbal thought that it offers a feeling of exhilaration. 
     To achieve this pace, recognition of ten thousand letters or more, labeling of thousands of words, and understanding of the meanings of words and sentences are all accomplished within a minute. This is perhaps ten times faster than the usual pace of verbal thought, and entails the added steps of recognition and labeling. Clearly recognition and labeling are accomplished rapidly. 
     The Dwordle Completes a Feedback Loop Between the Visual Field and Verbal Analysis: 
     Thus, there is a highly tuned channel from the visual field to verbal analysis. To complete the feedback loop that is necessary to achieve effective coordination between these two modes of analysis, a reverse pathway from verbal to visual analysis must be opened. Written language and accurate drawing have provided the basis for this. 
     The traditional pathway from verbal to visual is writing and drawing. Almost everyone has had the experience of taking notes while someone else is explaining something or while studying. Most of us are also familiar with adding diagrams to our notes to clarify relationships. Our hands create the letters and images that send our ideas to the visual field. 
     Many of us also made random drawings on the pages of the notebook. These random drawings are called “doodles.” 
     A “doodle” is “an unfocused drawing made while a person&#39;s attention is otherwise occupied.” 
     Doodling can aid a person&#39;s memory by expending just enough energy to keep one from daydreaming, which demands a lot of the brain&#39;s processing power, while also helping the person to continue paying attention. Thus, it acts as a mediator between the spectrum of thinking too much and thinking too little, and helps focus on the current situation. 
     The “Dwordle”. Here we suggest the term “dwordle” (pronounced dwurr-dull) to describe a doodle that is primarily made up of words and is used for the specific purpose of feedback from verbal analysis through broad minding to the visual field. A dwordle is the most direct form of feedback from verbal to visual analysis. The dwordle shares two key features with a doodle. Like a doodle, the material is selected at random rather than by verbal analysis. Again like a doodle, there is an element of random drawing in the dwordle, because the positioning of the words is left open to be randomly determined. 
     The strength of the dwordle arises from broad minding. The selection of words and the positioning of words is “at random” in the sense that we do not do it intentionally, but it is not truly random. On the contrary, words and positions are selected subliminally in support of our purpose. 
     Dwordling: 
     We use the dwordle while seeking to advance a project of productive thought, and we invite broad minding to help us achieve our purposes. The words in a dwordle are brought up to consciousness without prior conscious attention, and without conscious design on our part the words are positioned among other words on the page. 
     Broad minding cooperates by selecting words and positioning those words to evoke fresh insights for verbal analysis. From our conscious perspective, this is like free association. But our clear purpose in carrying out the exercise allows broad minding to cooperate by presenting useful associations. 
     The purpose of the dwordle is to express the current state of conscious conceptual thought with key words that come up through free association, and allow them to place themselves on a page in a freely selected configuration. The outcome is like a keyword outline in the shape of a diagram. The wide-angle visual field knows how to see the dwordle as a whole, and also knows how to infer relationship. Receiving messages from visual analysis, verbal analysis immediately forms new connections and reorients old ones in ways that were not previously accessible. 
     The addition of each word is another step in the process. One feedback loop from verbal to visual thought and back to verbal thought is completed with each step. At each step, broad minding is choosing a key word and placing it on the diagram. Broad minding does not need to do this in a linear fashion; instead it draws upon the formal structure of verbal analysis in a way that is not subject to the constraints of conscious formal thought. 
     As the process unfolds, the visual field is taking in the words as they are written, juxtaposing them with one another and considering their relations through visual analysis. Seeing them emerge successively one by one, and at all times seeing simultaneously all words so far written, the visual field opens the design up to broader minding. In turn, broader minding brings up the words and shapes the layout to show evocative relationship. 
     Broad minding seeks to make fresh relationships available to supplement the present state of verbal analysis. It selects words (labels) that are relevant for connection, choosing them from among the existing connections in the formal framework of conceptual thought as well as from remote locations. Then it presents them to consciousness in a diagram that suggests relationships. As a result, fresh relationships can be received and recognized through the wide-angle visual field. 
     In simple terms, dwordling exports the field of verbal analysis from broad minding to the written word and presents it as a diagram for the visual field, where it is visually analyzed and presented freshly to the field of verbal analysis to be rearticulated. 
     Using Dwordling in a Project: 
     Dwordling is designed to support purposeful verbal analysis. As described above, dwordling can be used throughout a project to creatively explore connectivity in the material. In addition, four occasions in a project are particularly well suited to spontaneous dwordling: (1) at the outset of a project; (2) when obstacles arise and the way forward is unclear; (3) to validate what has been accomplished and check things out; and (4) when a milestone is reached and the author is pausing or finishing the project. 
     At the start the author softens his gaze and settles into wide-angle focus. The author selects a word at random from the inventory of terms provided by the overlay builder  56 , and places the word at random in the visual display  60 , or alternatively types in a new term at the selected point, as a node for consideration to include in the overlay  41 . The author chooses the words by free association and positions them flexibly, leaving open the opportunity for the words to “choose their own place” on the visual display  60 . 
     Preferably, the author does not think purposefully about what he is doing or what is happening. Instead, the author waits for insight to come. When an insight comes, the author enters a comment, for example by attaching the comment to the node containing the dwordle. The author then explores the comment to the minimum degree needed to clarify its nature before returning to the dwordle. 
     When dwordling seems to be losing energy and new words are not coming to mind, the author looks at the visual field  60  in its entirety, like a drawing. The author does not focus on any single word or phrase, but instead softens his gaze into wide-angle focus and sees all of the words, nodes and the visual field  60  as a whole like a drawing. While the author contemplates the page, he relaxes mentally and lets new words or phrases come into consciousness, for example by randomly scanning the inventory of terms. If new words come, the author carries the process further. When the author has the insights he needs, he can let the formal process come to an end. Further insights may arise after dwordling is complete. Once the dwordling is complete, the author has a set of nodes and connections to use as a start on building the overlays or electronic books of an embodiment. 
     Other Assistance for Productive Thought: 
     Turning to other beneficial aspects of embodiments of the invention, as an author works in the overlay builder  56 , or other embodiments of a creative development environment, the available tools as discussed above naturally interface closely with the author&#39;s mental processes. 
     Relaxing into Alert Wide-Angle Focus: 
     In contrast to linear conscious thought, which sequentially presents thoughts or images or feelings, when creative work is being seen in the wide-angle visual field the thought process can be largely subliminal and can proceed simultaneously on many levels. In these circumstances, conscious thought is usually not called for, and the conscious thoughts that do occur are likely to distract rather than contribute. Concentrating on your efforts in a relaxed way, you may find that effortful feeling tends to fall away. Concentration arises naturally from your interest in the work and sustains you through long hours of alert attention without causing weariness. 
     Whether you are writing on a page or typing on a keyboard, the meanings that you experience seem to come forth through your fingers rather than your thoughts. You no longer consciously anticipate what will be presented, but instead let conscious meaning take shape in silence as the words appear under your restful gaze. You can always try out some words or images in your thoughts, and when you do these experiments may be fruitful, but much of the time the material just shapes itself. The knowledge reflected in your work seems to unfold naturally, almost magically, without any evident source or accompanying commentary. 
     The forceful flow of conscious thought may feel continuous, but in fact these thoughts are surfacing from vast potentiality like foam on an ocean wave composed of water from the ocean&#39;s depths. Successive thoughts often arise from diverse sources in mind, like entertainers selected for a variety show who come from different backgrounds, or customers exiting through a revolving door who were shopping in different parts of the store a few moments before. 
     Electronic Textbook Components Taking Shape: 
     A thought may have its own cohesion, or it may be unpolished. When a series of thoughts are cohesive they are more like a paragraph, which again may be cohesive or lacking completion. When a paragraph announces its own completion and settles into context, you may have found a feature or part of a feature. This feature is implemented as a node in the overlay  41  or electronic textbook  5 , as discussed above. 
     Sometimes thoughts may be intensely interesting and even thrilling. Such thoughts may become connectors in your finished work, such as the connections  7  of the electronic textbook  5  or overlay  41  as discussed above. Often connections will be implicit, unexplored by conscious thought and not easy to find, and they may be all the more interesting for that reason. 
     If you are lucky enough to experience space between your thoughts, you may be able to find connections easily, present latently in that quietness. If not, you can sense connectivity in the sequential stream of meaning and alertly grasp it. Some connections are logical, but the most valuable or profound ones relate less to inference and more to observation: they are present because of knowledge that has not yet been consciously articulated, and when you observe them in context insights will come. 
     Many other connections are associations derived from your past experience or alive in your present circumstances, These are meaningful to you but not necessarily to others, and more likely to resound with emotional tones. It is often difficult to extract the meanings of streaming thoughts from the emotions that accompany them, and you may find that the gentle accommodation and neutrality of wide-angle vision offer welcome relief, allowing meanings to shed their emotionality and clarify themselves effortlessly. 
     Each feature, when well established, readily defines its connections in your thoughts, and each connection, when well established, clarifies and helps to define the features to which it connects. Working in the display area  60  of the overlay builder  56 , you find that meaning sometimes crystallizes at a rapid pace, too quickly for conscious comprehension. You may wish to pause and check out what has emerged by tracing its connections and features (e.g. connections  7  and nodes  10 ) with linear thought, but it is often much better to let the flow continue. Hold on to this perspective: the mental capabilities available to you are vast beyond conscious understanding, so when your work is going well let your mind manage your conscious experience rather than trying to consciously manage your mind. 
     As you adhere to this perspective and gain confidence, the space between the thoughts will open up to you. 
     When your work in the display area  60  is going well, it can be useful to let go of any thoughts about where you are going. Features and connections (e.g. connections  7  and nodes  10 ) can be shaped by rounding out their attached texts (e.g. comments as discussed above), and the network (e.g. the overlay  41  or electronic textbook  5 ) can be extended and filled in as appropriate, refining and enriching its connectivity. You are working at the detail level, articulating and mapping your knowledge. 
     Focusing on your Audience: 
     When your thoughts do turn to the wider implications of your efforts it may be a good time to hone in on the usefulness of your work for others. Which features and which connections might be most interesting? Are their different audiences out there, different user communities with different styles and preferences? Visualize the people you know and wonder about which feature might be their favorite, which connection might be most useful for them? 
     Such questions open up the dimension of paths (such as the paths  12 ,  14 ,  16  through the electronic textbook  5  of an embodiment): What paths through the material would be most helpful to others? 
     Is there one main path with optional branches, or are there several paths that deserve to stand alone? Should there be only one gateway or several? 
     When people approach your material, will they be able to determine what suits them from brief descriptions or will it be better to plan a way for them to enter your material and explore it before making up their mind. Are their topics in the heart of your material that might deserve special access points leading to small focused paths? 
     Contemplating your Material: 
     Your material may have a dominant order such as sequence in time, or it may have a dominant layer such as regions in a travel guidebook. Your material may naturally divide into units, like recipes; or themes, like elements of design; or chapters with a common structure such as an idea accompanied by examples, exercises and tests of skill. There may be multiple paths through the material, and these may be at different levels or with different topics. 
     As you plan your work and pursue it you&#39;ll notice attributes that apply to some features or connectors and not others. Whenever you find that you want to check the consistency or continuity of similar things, you will probably want to assign them a common attribute. These attributes will help you to work with the material, and since they explicitly capture an aspect of your material, they may be useful for users later on. 
     Features that are similar, widespread and distinct, such as examples or exercises, can become a layer. Features that are interrelated in an orderly way, such as parallel paths or regularly encountered stages can be ordered in a structure. Layers and structures can be presented in customized displays that make them easier for you to work with as a whole and easier for your users to understand. 
     Visual Logic: 
     Our modern world is increasingly complex, and our abilities to cope with complexity are also increasing. The tools offered in embodiments of the invention can help you to validate your thought process and master complexity. You may find that you can lay out the relevant factors that convince you that a relationship exists but you are not sure exactly how they interact. It makes sense to write the factors down on a sheet of paper and diagram the interactions with arrows and comments. 
     After you work out the diagram you can transcribe it to an overlay  41  in the visual display  60  of the overlay builder  56  (or similarly to an electronic textbook  5 ). Alternatively you can complete the whole process from start to finish in the display field  60  of the overlay builder  56 , and when you have it right the features and connections (e.g. nodes  10  and connections  7 ) will be available for later use. You can create a special path that traces the logic in whatever way seems most transparent, and you naturally lay out the connections in comments attached to the connectors. 
     When an interaction is highly complex, it is helpful to prepare a logic view. After you make an inventory of the interactions, consider whether some of them arise from common underlying factors. If so, then it may be helpful to trace each of their separate influences during your exposition. Each of these underlying factors can determine a logical nexus: a node dedicated to displaying an aspect of the underlying logic. 
     Interactive Logic Views: 
     As an author, one of the best ways of helping your users and clarifying your understanding is to create interactive pages. The presentation of a logical argument in a logic view by tracing through underlying logical nexuses, connectors and features—just mentioned above—illustrates this. When teaching, many procedures and relationships can best be made clear through interactive question and answer sessions, examples and exercises. Often such cases are presented dynamically through interactivity on a single page, or by automated navigation through a cluster of related pages. Interactivity can be a great aid to understanding. Visualizing and planning the interaction is even better. We are able to learn through experience and develop an intuitive appreciation of what we are learning and how it is important. 
     Speedy Content Development: 
     Rapid success in developing content such as the overlay  41  or electronic textbook  5  comes from attending to details and the broad picture simultaneously, while keeping in mind major aspects intermediate between these two poles. This is not possible in conscious thought, but the broader capabilities of mind are up to the task when you have become familiar with the material, and the material is well articulated and clearly presented to the visual field. Visual display can facilitate remarkable progress. 
     The tools in the overlay builder  56  are designed for this purpose. The visual display  60  can display the global view in its entirety or contracted to higher levels, or it can be selectively displayed by layers or attributes or structures. The tabular grid  61  can give you access to any sorted order of any filtered subset of features or connectors or both. Anything selected in the visual display  60  can be displayed in the tabular grid  61  and vice versa. Any selection can be displayed at any level of detail, including associated text in its entirety or only at the level of embedded outline headings. 
     There is also a Comprehensive view that offers any path through the material in document or webpage form. If the material consists of text and images, it is displayed in printable form that corresponds to sequential printing of a path in the overlay builder. 
     Other Applications of the Overlay: 
     The overlay  41  of embodiments of the invention is very versatile. The overlay  41  allows a user to easily assemble diverse materials and enter the user&#39;s own comments and transitions. It can assimilate and images or texts. The user can interlink the images or texts, select any path through the overlay  41 , and print that path linearly. 
     Personal Uses: 
     For example, the user can combine driving directions with personal photos, add explanatory comments and send these out as an invitation that can be played in a tablet equipped with the browser add-on  40 , as the user&#39;s guests are driving to the event. 
     The user can create a travel diary during a trip, linking the user&#39;s own photos and videos with images from the web, entering comments and editing flexibly during the trip, and after the user returns. Other users such as family members can create different paths through the same travel diary material for different purposes, and print them out when needed. One path might become a class report in school, another sent to relatives and friends, another become a treasured personal record. 
     The user can assemble a library of audio-visual playlists together with comments, each a different path through a common library of audio and images. 
     The user can begin with a library of recipes assembled from diverse sources, and overlay it using an overlay  41  with comments and menu suggestions. Paths are created reflecting each meal, connecting multiple recipes in order. Then, without disturbing the basic recipe library in any way the user assembles a multi-day menu with all the necessary comments as a distinct path. This is an application of a multi-level hierarchical overlay as discussed above: courses included in menus sequenced over days and weeks. Over the years, the user can accumulate hundreds of these sequential paths through the library. 
     In all these applications, the various paths created in the overlay  41  can be read as a path on the computer or tablet, using the overlay builder  56  or an add-on  40 , or printed out in the traditional way. The user can also share this work with others, allowing them to contribute to what the user has created. 
     Website builder. The website builder can also create general electronic books (but not electronic textbooks). It has all the capabilities of the Author&#39;s Workbench, along with additional general-purpose capabilities relating to connectors, informed choice and perspectives. It also deals with arrangements and security issues. 
     Website Applications: 
     In another embodiment, an electronic book or an overlay of existing source material is created, which integrates in a single compilation material from multiple sources, such as multiple conventional books. Each separate source is represented in the compilation as a path through the compilation. The compilation has many entry points, for example one entry point for each discrete source (e.g. book). Each entry point offers a different angle of approach to the compilation. Each entry point opens to a path through the compilation that presents its own topic (e.g. the topic presented by the underlying source). However, because the underlying sources are all collected together into a single compilation with multiple paths through the compilation, a user of the compilation has access to a wide range of choices when connecting the material together with other relevant topics. These connections may be created by an author of the compilation, for example by creating a connection between two related topics in two sources in the compilation. Thus, if the compilation compiled several religious texts, the author could logically connect the same story told in each text, such that a user navigating the compilation could explore multiple viewpoints about that story, as expressed in each underlying text. 
     In another embodiment, a central organization (such as the Audubon society) maintains a public web resource (such as an individual photo of each bird in America with accompanying text description), and offers to users (for example chapters and/or individual members) the ability to make a local exhibit as an overlay. Construction of the local overlay is semi-automatic: Beginning with the list of local entities provided by the user (such as birds), possibly supplemented by a sequential order (for example local counts), an overlay that visits the list of descriptions is initially created. Then the user is free to insert comments and further material (such as local photos) to supplement the basic resource and complete the presentation. The local overlay then joins a collection of other local overlays, which can be made publicly available through the central organization&#39;s website and/or local websites as preferred. Over and above the intrinsic value of these local presentations, the process elicits local information that is valuable to the central organization. 
     Electronic Books: 
     Additional embodiments of the electronic book or overlay include the following examples: 
     Literature: 
     Many stories concern two or three diverse characters. Usually the narration lays out their interactions and their thoughts, sometimes quoting their words. An electronic book according to embodiments of the invention straightforwardly presents the story line from the perspective of each of the characters. Each character&#39;s personal narrative is a distinct path through the nodes of the book, with a series of key scenes narrated by the author as a central path. Some of the nodes would be shared by multiple paths, and some of the nodes would be unique to a given character&#39;s narrative. Additionally, some nodes could supply different content depending on the path by which the reader arrived. Thus a node regarding a key point to the plot could present the same content (e.g. a view of a key scene) but alter the view to reflect the perspective of the path for the character the reader was following. A presentation of this kind gives the author&#39;s characters the scope to fully express their personal qualities. The reader of such an electronic book can choose to follow the narrative of any of the characters, thus experiencing a different book on each traversal through the electronic book. 
     Laying Out Fields of Knowledge: 
     Many widely read articles and books offer overviews of fields and topics of knowledge, striving for timeliness and often laden down with references to varied publications. The same work could be done much more effectively as an electronic book of an embodiment, using the techniques mentioned with reference to the overlay  41  above. An overlay  41  is constantly updated, keeping it always current. Such an enterprise could be a cooperative venture. 
     Working through Cognitive Difference or Contention: 
     Using an electronic book or overlay of an embodiment, as discussed above, to make a record of statements from opposing viewpoints and beliefs, or from contending parties can do justice to each of the different sides. Each party receives a distinct path that traces their positions and reasoning, while a path along the middle ground offers a balanced perspective on the distinct positions. An approach like this is a natural expression of good journalism and potentially an aid to reconciliation. 
     Tracking Changes in Human Culture: 
     Culture at any point in time is many-faceted. Over time these facets change as culture changes. Offering an overlay containing connections to multiple facets of human culture at each point of time, captured as nodes in the overlay—a cross-section of culture at that moment, and then layering successive cross-sections as additional overlays, or layers to the overlay as discussed above, to create a history will offer a compelling record. The overlay of an embodiment of the invention is ideally suited to turn a structured matrix of information into an intelligible and interesting presentation. 
     Technical Documentation: Clarifying Complex Systems: 
     The world is increasingly complex. Gadgets have more options, increasingly complex controls to manage those options, and more and more potential points of failure and confusion for the user. One of the side effects of this is that it&#39;s increasingly easy to find a solution on the web. Printed user-manuals and generic web-based comments are increasingly supplanting documentation from the gadget&#39;s manufacturer. 
     The electronic books and overlays of embodiments as discussed above are excellent vehicles for technical documentation in every form, with qualities ideally suited for the creator, the users and third-party documenters. 
     The complexity of many systems arises from many interacting elements. A system may be unstable or stable, fixed or changing depending on how the interacting forces balance out. Simulations of such systems can calculate their behavior, but this is not always sufficient to explain their workings. The overlay of an embodiment is ideally suited to represent the interactions conceptually, allowing the various influences to be traced. 
     For example, the overlay of an embodiment is used to create the technical documentation for a new product or a new software program. When a designer is creating something, the designer takes into account many interactions among different elements of the design. Sometimes elements are connected by direct impact, either one-directional or reaching a mutual balance. Sometimes their design reflects a trade-off that gives rise to a point of vulnerability and potential failure. Sometimes a mutual interaction is hard to understand, and sometimes it depends on subtle factors elsewhere in the system. 
     Usually the more subtle interactions between features in the design are not clearly apparent in conventional documentation, but the overlay of an embodiment allows their importance to be clearly acknowledged. Each feature or design element of the new product is reflected in a node of the overlay. Then, each such interaction is recorded by its own connection between the nodes reflecting the features involved. 
     Documenting Computer Code: 
     The overlay of an embodiment makes the logical structure clear, by representing this logical structure using the nodes and connections of the overlay. For example in well-designed object-oriented software the logical structure of the program&#39;s functions is reflected in the structure of the program, including for example the various objects which call each other, or the various routines that invoke each other, when the program is executed. The overlay containing the technical documentation can be attached to the code objects with links that parallel these functional interactions. In fact, a complete structure for the documentation overlay could be read out from the computer code. 
     The overlay of an embodiment can go beyond the simple reading out of structure from computer code in a very important way, because interactions in the code are generally so intricately intertwined that no single framework can reflect them. Code follows the logical structure of some interactions but becomes perpendicular to others, and cannot possibly represent them all. By contrast, as an overlay, the overlay of an embodiment easily overcomes these problems by adding connections for as many additional structures as necessary. Each structure becomes a distinct layer in the documentation, and layers can be cogently compared and contrasted in compelling visual perspectives. 
     Living Documentation: 
     Furthermore, the usual forms of documentation do not age well. They are inadequate to begin with and as a project is enhanced and extended the documentation falls further and further behind. 
     One important cause of this is that the linear, tree-structure of documentation gets in the way of revisions. When leaves on distant branches become closely interconnected, there is no way for conventional documentation to emphasize this transparently. 
     Often enhancements and extensions come into being because the original design was inadequate, so innovations naturally violate assumptions that pervaded the original version. But it is not worth the effort to reorganize the entire tree to reflect the changes, and so the documentation loses its integrity and fades into irrelevance. 
     The overlay of an embodiment facilitates technical documentation that is living, active and in depth. As soon as someone understands a way to improve the documentation, they can add in the links and nodes to implement the improvement. 
     As an illustration, suppose that a software developer opened up its comprehensive documentation to outside users, such as user-manual publishers, to create overlays on the internal documentation using embodiments of the invention. In a short time the software developer&#39;s own people might be navigating through their own documentation using the nodes and connections in an overlay of an embodiment, which was created by the outside users. Of course all the outside users would be doing the same thing. Soon the software developer&#39;s people would better understand what they were doing and communicate better with one another, and as a result programming performance would improve and become more user-friendly. 
     Once the documentation is enhanced with an overlay, it can be seamlessly updated. For example, if a user identifies a gap in the product documentation, or a design flaw in the product, or an implementation bug, the user can diagnose the problem, create an update to the documentation, or a work around for the flaw or bug, and the new content is assimilated seamlessly into the existing documentation, via the overlay. The newly prepared explanation is accessible through its own path, with its own entry gateway keyed to the problem, and presents the solution through comments added in the overlay and citations from the underlying documentation. 
     Medicine: Integrating Clinical Experience and Scientific Discovery into a Coherent Framework: 
     These overlays can also be used to help translate complex knowledge into practical forms. For example, users building overlays can integrate together clinical experience and scientific discovery into a mutually coherent framework. Conventional clinical medicine largely relies upon rule-based treatment consequent upon diagnosis, and is not well suited to complex illnesses or illnesses that are hard to diagnose. Alternative medicine is more likely to approach each patient as a unique and complex biological system to be investigated in depth and progressively understood more and more incisively until eventually a cure is reached. Science approaches the human body as a system but tends to focus on general rather than individual characteristics and circumstances. Each of the three approaches has great strengths in its own domain, but it seems that the alternative clinician is positioned at the nexus between science and conventional treatment, because this is the point where individual characteristics are investigated in depth. Further, all three will benefit from increased knowledge of the human system, and the key to success is to consider patients who are ill with complex, hard to diagnose illnesses—the same patients who would normally seek out alternative treatment—as the platform for advancing basic science and translating scientific knowledge into practice. In an embodiment, the three separate orientations are each distinctly articulated and then juxtaposed, using the overlays on top of a core set of information such as a given patient&#39;s medical history. This approach allows widely disparate approaches to cohere around a new orientation, and facilitates the ultimate treatment of the patient. 
     Systematic Translation of Religious Literature: 
     For example, the Tibetan Buddhist Canon includes more than 200,000 pages, not including more than a millennium of additional domestic material. Translation into English is well underway, but the initial translation from Sanskrit to Tibetan that began more than 1200 years ago maintained high standards of consistency that are not natural in the West, and there is no agreement as yet as to lexicon or style for the translation to English. 
     The overlays of an embodiment can facilitate cooperation among a team of translators, by overlaying diverse translations that are all pegged to the Tibetan originals to which they refer. The Tibetan originals supply the underlying information items as discussed above. The various translations created by each translator form overlays on top of the underlying information items. Each translation can create a different path through the underlying Tibetan original material, with the translated text and additional comments explaining the translations. 
     However the challenge goes well beyond aligning the translations with their originals, because the Tibetan Canon reflects great respect for precedent, so that memorable verse and prose from the Buddha and early masters spawns a tree of consistently translated quotations that extends down to the present day. The overlays of embodiments of the invention can map many hundreds of trees of this kind, perhaps as many as 1000. In many cases, there will be hundreds of branches on a tree. Think of each of the trees as analogous to a branching path, and visualize displaying the many trees extending over hundreds of thousands of pages. The purpose of this mapping effort is to allow translators to see all the usages of a passage throughout the canon as a whole and progress step by step toward definitive translations, agreeing on translation terminology first for these seminal phrases that are so widely quoted, and central to the language as a whole. Without this approach, consistency will be unattainable because various translators will naturally translate the same passage in diverse ways in the many contexts where it appears. In an embodiment, the overlay is used to create a translation platform that will be widely used by translators around the world, allowing them to share information and support one another&#39;s projects. 
     In the foregoing specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. For example, the reader is to understand that the specific ordering and combination of process actions described herein is merely illustrative, unless otherwise stated, and the invention can be performed using different or additional process actions or a different combination or ordering of process actions. Similarly, the orderings of the user traversals through the nodes and connections of the overlays and electronic books of the embodiments are merely illustrative. As another example, each feature of one embodiment can be mixed and matched with other features shown in other embodiments. Features and processes known to those of ordinary skill may similarly be incorporated as desired. Additionally, features may be added or subtracted from the various embodiments or embodiments can be combined. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.