Copyright
Copyright  symbolized ""  is a legal concept enacted by most national governments, that gives the creator of an original work exclusive rights to it, usually for a limited period of time.  At its most general, it is literally "the right to copy", but also gives the copyright holder the right to be credited for the work, to determine who (if anyone) may adapt the work to other forms, to determine who may perform the work, to benefit financially from the work, and other related rights.  It is one form of intellectual property (distinct from patents, trademarks, and trade secrets), and applies to any particular expression of an idea or information, which is substantial and self-contained in a fixed form.
Although initially conceived as a way for the government to restrict printing, the intent of modern copyright is to promote the creation of new works by giving authors the ability to control them and to profit from them for a limited time.  These rights have become standardized internationally, in most jurisdictions lasting 50-100 years after the death of the creator, or a fixed number of years for anonymous or corporate creations.  Although some jurisdictions have required formalities to establish copyright, most now recognize copyright in any completed work, without registration.  Copyright is generally enforced by the creator as a civil matter, though some jurisdictions also apply criminal sanctions.
Most jurisdictions recognize some limitations to copyright, allowing "fair" exceptions to the creator's exclusivity and giving certain rights to consumers.  The development of digital media and networking technologies have prompted reinterpretation of these exceptions, introduced new difficulties in enforcing copyright, and inspired additional challenges to the philosophical basis for the law.  Simultaneously, businesses with substantial economic dependence on copyright have advocated for the extension and expansion of their rights, and sought additional legal and technological means to enforce them.

# Scope
Copyright may apply to a wide range of creative, intellectual, or artistic forms, or "works".  Specifics vary by jurisdiction, but these can include poems, theses, plays, other literary works, movies, dances, musical compositions, audio recordings, paintings, drawings, sculptures, photographs, software, radio and television broadcasts, and industrial designs. Graphic designs and industrial designs may have separate or overlapping laws applied to them in some jurisdictions.
Copyright does not cover ideas and information themselves, only the form or manner in which they are expressed.  For example, the copyright to a Mickey Mouse cartoon restricts others from making copies of the cartoon or creating derivative works based on Disney's particular anthropomorphic mouse, but doesn't prohibit the creation of other works about anthropomorphic mice in general, so long as they're different enough to not be judged copies of Disney's.  In many jurisdictions, copyright law makes exceptions to these restrictions when the work is copied for the purpose of commentary or other related uses (See Fair Use, Fair Dealing). Meanwhile, other laws may impose additional restrictions that copyright does not - such as trademarks and patents.
Copyright laws are standardized somewhat through international conventions such as the Berne Convention and Universal Copyright Convention.  These multilateral treaties have been ratified by nearly all countries, and international organizations such as the European Union or World Trade Organization require their member states to comply with them.

# Theoretical basis
Copyright law as it is known today was originally established by legislative acts which cited two fundamental justifications for it: 1) to benefit society by promoting the creation of new works, and 2) to protect the moral rights of the creators of these works.
For example, the Copyright Clause of the United States Constitution (1787) authorized copyright legislation: "To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries."  That is, by guaranteeing them a period of time in which they alone could profit from their works, they would be enabled and encouraged to invest the time required to create them, and this would be good for society as a whole.  A right to profit from the work has been the philosophical underpinning for much legislation extending the duration of copyright, to the life of the creator and beyond, to his heirs.
The earlier Statute of Anne (1709) further alluded to individual moral rights, beginning: "Whereas Printers, Booksellers, and other Persons, have of late frequently taken the Liberty of Printing... Books, and other Writings, without the Consent of the Authors... to their very great Detriment, and too often to the Ruin of them and their Families:..."  A right to benefit financially from the work is articulated, and court rulings and legislation have recgonized a right to control the work, such as ensuring that the integrity of it is preserved.  An irrevocable right to be recognized as the work's creator appears in some countries' copyright laws.

# History
Copyright was invented after the advent of the printing press and with wider public literacy. As a legal concept, its origins in Britain were from a reaction to printers' monopolies at the beginning of the eighteenth century. Charles II of England was concerned by the unregulated copying of books and used the royal prerogative to pass the Licensing Act of 1662, which established a register of licensed books and required a copy to be deposited with the Stationers Company, essentially continuing the licensing of material that had long been in effect.
The Statute of Anne was the first real copyright act, and gave the publishers rights for a fixed period, after which the copyright expired. Copyright has grown from a legal concept regulating copying rights in the publishing of books and maps to one with a significant effect on nearly every modern industry, covering such items as sound recordings, films, photographs, software, and architectural works.
The 1886 Berne Convention first established recognition of copyrights among sovereign nations, rather than merely bilaterally. Under the Berne Convention, copyrights for creative works do not have to be asserted or declared, as they are automatically in force at creation: an author need not "register" or "apply for" a copyright in countries adhering to the Berne Convention. As soon as a work is "fixed", that is, written or recorded on some physical medium, its author is automatically entitled to all copyrights in the work, and to any derivative works unless and until the author explicitly disclaims them, or until the copyright expires. The Berne Convention also resulted in foreign authors being treated equivalently to domestic authors, in any country signed onto the Convention.  The UK signed the Berne Convention in 1887 but did not implement large parts of it until 100 years later with the passage of the Copyright, Designs and Patents Act of 1988. The USA did not sign the Berne Convention until 1989.
The United States and most Latin American countries instead entered into the Buenos Aires Convention in 1910, which required a copyright notice (such as "all rights reserved") on the work, and permitted signatory nations to limit the duration of copyrights to shorter and renewable terms.  The Universal Copyright Convention was drafted in 1952 as another less demanding alternative to the Berne Convention, and ratified by nations such as the Soviet Union and developing nations.
The regulations of the Berne Convention are incorporated into the World Trade Organization's TRIPS agreement (1995), thus giving the Berne Convention effectively near-global application.  The 2002 WIPO Copyright Treaty enacted greater restrictions on the use of technology to copy works in the nations that ratified it.

# Obtaining and enforcing copyright
Typically, a work must meet minimal standards of originality in order to qualify for copyright, and the copyright expires after a set period of time (some jurisdictions may allow this to be extended). Different countries impose different tests, although generally the requirements are low; in the United Kingdom there has to be some 'skill, labour and judgment' that has gone into it.  In Australia and the United Kingdom it has been held that a single word is insufficient to comprise a copyright work. However, single words or a short string of words can sometimes be registered as a trademark instead.
Copyright law recognises the right of an author based on whether the work actually is an original creation, rather than based on whether it is unique; two authors may own copyright on two substantially identical works, if it is determined that the duplication was coincidental, and neither was copied from the other.
In all countries where the Berne Convention standards apply, copyright is automatic, and need not be obtained through official registration with any government office.  Once an idea has been reduced to tangible form, for example by securing it in a fixed medium (such as a drawing, sheet music, photograph, a videotape, or a computer file), the copyright holder is entitled to enforce his or her exclusive rights.  However, while registration isn't needed to exercise copyright, in jurisdictions where the laws provide for registration, it serves as prima facie evidence of a valid copyright and enables the copyright holder to seek statutory damages and attorney's fees.  (In the USA, registering after an infringement only enables one to receive actual damages and lost profits.)
The original holder of the copyright may be the employer of the author rather than the author himself, if the work is a "work for hire".  For example, in English law the Copyright Designs and Patents Act 1988 provides that if a copyrighted work is made by an employee in the course of that employment, the copyright is automatically owned by the employer which would be a "Work for Hire."
Copyrights are generally enforced by the holder in a civil law court, but there are also criminal infringement statutes in some jurisdictions.  While central registries are kept in some countries which aid in proving claims of ownership, registering does not necessarily prove ownership, nor does the fact of copying (even without permission) necessarily proof that copyright was infringed.  Criminal sanctions are generally aimed at serious counterfeiting activity, but are now becoming more commonplace as copyright collectives such as the RIAA are increasingly targeting the file sharing home Internet user. Thus far, however, most such cases against file sharers have been settled out of court. (See: File sharing and the law)

## Copyright notices in the U.S.
Prior to 1989, use of a copyright notice  consisting of the copyright symbol (Template:Unicode, the letter C inside a circle), the abbreviation "Copr.", or the word "Copyright", followed by the year of the first publication of the work and the name of the copyright holder  was part of United States statutory requirements. Several years may be noted if the work has gone through substantial revisions. The proper copyright notice for sound recordings of musical or other audio works is a sound recording copyright symbol (Template:Unicode, the letter P inside a circle), which indicates a sound recording copyright.  Similarly, the phrase All rights reserved was once required to assert copyright.
In 1989, the U.S. enacted the Berne Convention Implementation Act, amending the 1976 Copyright Act to conform to most of the provisions of the Berne Convention.  As a result, the use of copyright notices has become optional to claim copyright, because the Berne Convention makes copyright automatic. However, notice of copyright using these marks may have consequences in terms of reduced damages in an infringement lawsuit.

## "Poor man's copyright"
A widely circulated strategy to avoid the cost of copyright registration is referred to as the "poor man's copyright".  It proposes that the creator send the work to himself in a sealed envelope by registered mail, using the postmark to establish the date.  This technique has not been recognized by any United States court, and is dismissed as meaningless by the United States Copyright Office.  However, the UK Patent Office suggests it as one method of proving the originality of a work as of the postmark date.

# Exclusive rights
Several exclusive rights typically attach to the holder of a copyright:
- to produce copies or reproductions of the work and to sell those copies (including, typically, electronic copies)
- to import or export the work
- to create derivative works (works that adapt the original work)
- to perform or display the work publicly
- to sell or assign these rights to others
- to transmit or display by radio or video
The phrase "exclusive right" means that only the copyright holder is free to exercise those rights, and others are prohibited from using the work without his permission.  Copyright is sometimes called a "negative right", as it serves to prohibit certain people (e.g., readers, viewers, or listeners, and primarily publishers and would be publishers) from doing something they would otherwise be able to do, rather than permitting people (e.g., authors) to do something they would otherwise be unable to do.  In this way it is similar to the unregistered design right in English law and European law.  The rights of the copyright holder also permit him/her to not use or exploit their copyright, for some or all of the term.
There is, however, a critique which rejects this assertion as being based on a philosophical interpretation of copyright law that is not universally shared. There is also debate on whether copyright should be considered a property right or a moral right. Many argue that copyright does not exist merely to restrict third parties from publishing ideas and information, and that defining copyright purely as a negative right is incompatible with the public policy objective of encouraging authors to create new works and enrich the public domain.
The right to adapt a work means to transform the way in which the work is expressed.  Examples include developing a stage play or film script from a novel, translating a short story, and making a new arrangement of a musical work.

# Limits and exceptions to copyright

## Idea-expression dichotomy and the merger doctrine
Immanuel Kant in his 1785 essay Von der Unrechtmaigkeit des Buchernachdrucks distinguishes the physical from the ideational, the thought involved from the book. This distinction is of critical importance to the near constant wrangling between publishers, other intermediaries, and the original, creative authors.
Copyright usually protects the expression of an idea, not the idea itself  in US jurisprudence this is called the idea/expression or fact/expression dichotomy. For example, if a writer has a general concept or idea for a television program, the law of copyright does not prohibit other writers from copying that general idea. However, if the writer develops the idea so that it constitutes a detailed storyline or plot, then that may be protected by copyright, notwithstanding that it is "idea" rather than "expression". Similarly, the translation of a literary work will constitute an infringement of copyright, notwithstanding that no element of the "expression" is directly copied.
Another example could be if a book is written describing a new way to organize books in a library, a copyright does not prohibit a reader from freely using and describing that concept to others; it is only the particular expression of that process as originally described that is covered by copyright. One might be able to obtain a patent for the method, but that is a different area of law. Compilations of facts or data may also be copyrighted, but such a copyright is thin; it only applies to the particular selection and arrangement of the included items, not to the particular items themselves.  In some jurisdictions the contents of databases are expressly covered by statute.
In some cases, ideas may be capable of intelligible expression in only one or a limited number of ways. Therefore even the expression in these circumstances is not covered. In the United States this is known as the merger doctrine, because the expression is considered to be inextricably merged with the idea.  Merger is often pleaded as an affirmative defense to charges of infringement.  That doctrine is not necessarily accepted in other jurisdictions.

## The first-sale doctrine and exhaustion of rights
Copyright law does not restrict the owner of a copy from reselling legitimately obtained copies of copyrighted works, provided that those copies were originally produced by or with the permission of the copyright holder. It is therefore legal, for example, to resell a copyrighted book or CD. In the United States this is known as the first-sale doctrine, and was established by the courts to clarify the legality of reselling books in second-hand bookstores.  Some countries may have parallel importation restrictions that allow the copyright holder to control the aftermarket.  This may mean for example that a  copy of a book that does not infringe copyright in the country where it was printed does infringe copyright in a country into which it is imported for retailing. The first-sale doctrine is known as exhaustion of rights in other countries and is a principle which also applies, though somewhat differently, to patent and trademark rights. It is important to note that the first-sale doctrine permits the transfer of the particular legitimate copy involved. It does not permit making or distributing additional copies.
In addition, copyright, in most cases, does not prohibit one from acts such as modifying, defacing, or destroying his or her own legitimately obtained copy of a copyrighted work, so long as duplication is not involved. However, in countries that implement moral rights, a copyright holder can in some cases successfully prevent the mutilation or destruction of a work that is publicly visible.

## Fair use and fair dealing
Copyright does not prohibit all copying or replication. In the United States, the fair use doctrine, codified by the Copyright Act of 1976 as 17 U.S.C. Section 107, permits some copying and distribution without permission of the copyright holder or payment to same. The statute does not clearly define fair use, but instead gives four non-exclusive factors to consider in a fair use analysis. Those factors are:
- the purpose and character of your use
- the nature of the copyrighted work
- what amount and proportion of the whole work was taken, and
- the effect of the use upon the potential market for or value of the copyrighted work.
In the United Kingdom and many other Commonwealth countries, a similar notion of fair dealing was established by the courts or through legislation. The concept is sometimes not well defined; however in Canada, private copying for personal use has been expressly permitted by statute since 1999.  In Australia, the fair dealing exceptions under the Copyright Act 1968 (Cth) are a limited set of circumstances under which copyrighted material can be legally copied or adapted without the copyright holder's consent.  Fair dealing uses are research and study; review and critique; news reportage and the giving of professional advice (ie legal advice).  Under current Australian law it is still a breach of copyright to copy, reproduce or adapt copyright material for personal or private use without permission from the copyright owner. Other technical exemptions from infringement may also apply, such as the temporary reproduction of a work in machine readable form for a computer.
In the United States the AHRA (Audio Home Recording Act Codified in Section 10, 1992) prohibits action against consumers making noncommercial recordings of music, in return for royalties on both media and devices plus mandatory copy-control mechanisms on recorders.
Later acts amended US Copyright law so that for certain purposes making 10 copies or more is construed to be commercial, but there is no general rule permitting such copying. Indeed making one complete copy of a work, or in many cases using a portion of it, for commercial purposes will not be considered fair use. The Digital Millennium Copyright Act prohibits the manufacture, importation, or distribution of  devices whose intended use, or only significant commercial use, is to bypass an access or copy control put in place by a copyright owner. An appellate court has held that fair use is not a defense to engaging in such distribution.

## Transfer and licensing
A copyright, or aspects of it, may be assigned or transferred from one party to another. For example, a musician who records an album will often sign an agreement with a record company in which the musician agrees to transfer all copyright in the recordings in exchange for royalties and other considerations. The creator (and original copyright holder) benefits, or expects to, from production and marketing capabilities far beyond those of the author. In the digital age of music, music may be copied and distributed at minimal cost through the Internet, however the record industry attempts to provide promotion and marketing for the artist and his or her work so it can reach a much larger audience.  A copyright holder need not transfer all rights completely, though many publishers will insist.  Some of the rights may be transferred, or else the copyright holder may grant another party a non-exclusive license to copy and/or distribute the work in a particular region or for a specified period of time.  A transfer or licence may have to meet particular formal requirements in order to be effective; see section 239 of the Australia Copyright Act 1968 (Cth).  Under Australian law, it is not enough to pay for a work to be created in order to also own the copyright.  The copyright itself must be expressly transferred in writing.
Under the U.S. Copyright Act, a transfer of ownership in copyright must be memorialized in a writing signed by the transferor. For that purpose, ownership in copyright includes exclusive licenses of rights. Thus exclusive licenses, to be effective, must be granted in a written instrument signed by the grantor. No special form of transfer or grant is required. A simple document that identifies the work involved and the rights being granted is sufficient. Non-exclusive grants (often called non-exclusive licenses) need not be in writing under U.S. law. They can be oral or even implied by the behavior of the parties. Transfers of copyright ownership, including exclusive licenses, may and should be recorded in the U.S. Copyright Office. (Information on recording transfers is available on the Office's web site.) While recording is not required to make the grant effective, it offers important benefits, much like those obtained by recording a deed in a real estate transaction.
Copyright may also be licensed. Some jurisdictions may provide that certain classes of copyrighted works be made available under a prescribed statutory license (e.g. musical works in the United States used for radio broadcast or performance). This is also called a compulsory license, because under this scheme, anyone who wishes to copy a covered work does not need the permission of the copyright holder, but instead merely files the proper notice and pays a set fee established by statute (or by an agency decision under statutory guidance) for every copy made. Failure to follow the proper procedures would place the copier at risk of an infringement suit. Because of the difficulty of following every individual work, copyright collectives or collecting societies and performing rights organizations (such as ASCAP, BMI, and SESAC have been formed to collect royalties for hundreds (thousands and more) works at once.  Though this market solution bypasses the statutory license, the availability of the statutory fee still helps dictate the price per work collective rights organizations charge, driving it down to what avoidance of procedural hassle would justify.

## Similar legal rights
Copyright law covers the creative or artistic expression of an idea.   Patent law covers inventions.  Trademark law covers distinctive signs which are used in relation to products or services as indicators of origin, as does (in a similar fashion), Trade dress.  Registered designs law covers the look or appearance of a manufactured or functional article.  Trade secret law covers secret or sensitive knowledge or information.
Although copyright and trademark laws are theoretically distinct, more than one type of them may cover the same item or subject matter. For example, in the case of the Mickey Mouse cartoon, the image and name of Mickey Mouse would be the subject of trademark legislation, while the cartoon itself would be subject to copyright. Titles and character names from books or movies may also be trademarked while the works from which they are drawn may qualify for copyright.
Another point of distinction is that a copyright (and a patent) is generally subject to a statutorily-determined term, whereas a trademark registration may remain in force indefinitely if the trademark is periodically used and renewal fees continue to be duly paid to the relevant jurisdiction's trade marks office or registry. Once the term of a copyright has expired, the formerly copyrighted work enters the public domain and may be freely used or exploited by anyone.  Courts in the United States and the United Kingdom have rejected the doctrine of a common law copyright.   Public domain works should not be confused with works that are publicly available. Works posted in the internet for example, are publicly available, but are not generally in the public domain.  Copying such works may therefore violate the author's copyright.

## Useful articles
If a pictorial, graphic or sculptural work is a useful article, it is copyrighted only if its aesthetic features are separable from its utilitarian features.  A useful article is an article having an intrinsic utilitarian function that is not merely to portray the appearance of the article or to convey information.  The must be separable from the functional aspect to be copyrighted.
There are two primary approaches to the separability issue: physical separability and conceptual separability. Physical separability is the ability to take the aesthetic thing away from the functional thing. Conceptual separability can be found in several different ways. It may be present if the useful article is also shown to be appreciated for its aesthetic appeal or by the design approach, which is the idea that separability is only available if the designer is able to make the aesthetic choices that are unaffected by the functional considerations. A question may also be asked of whether an individual would think of the aesthetic aspects of the work being separate from the functional aspects.
There are several different tests available for conceptual separability. The first, the Primary Use test, asks how is the thing primarily used: art or function? The second, the Marketable as Art test, asks can the article be sold as art, whether functional or not. This test does not have much backing, as almost anything can be sold as art. The third test, Temporal Displacement, asks could an individual conceptualize the article as art without conceptualizing functionality at the same time. Finally, the Denicola test says that copyrightability should ultimately depend on the extent to which the work reflects the artistic expression inhibited by functional consideration. If something came to have a pleasing shape because there were functional considerations, the artistic aspect was constrained by those concerns.

## Duration
Copyright subsists for a variety of lengths in different jurisdictions.  The length of the term can depend on several factors, including the type of work (e.g. musical composition, novel), whether the work has been published or not, and whether the work was created by an individual or a corporation.  In most of the world, the default length of copyright is the life of the author plus either 50 or 70 years.  In the United States, the term for most existing works is a fixed number of years after the date of creation or publication.  Under most countries' laws, copyrights expire at the end of the calendar year in question.
The length and requirements for copyright duration are subject to change by legislation, and since the early 20th century there have been a number of adjustments made in various countries, which can make determining the duration of a given copyright somewhat difficult.  For example, the United States used to require copyrights to be renewed after 28 years to stay in force, and formerly required a copyright notice upon first publication to gain coverage.  In Italy and France, there were post-wartime extensions that could increase the term by approximately 6 years in Italy and up to about 14 in France.  Many countries have extended the length of their copyright terms (sometimes retroactively).  International treaties establish minimum terms for copyrights, but individual countries may enforce longer terms than those.
In the United States, all books and other works published before 1923 have expired copyrights and are in the public domain.  In addition, works published before 1964 that did not have their copyrights renewed 28 years after first publication year also are in the public domain, except that books originally published outside the US by non-Americans are exempt from this requirement, if they are still under copyright in their home country (see How Can I Tell Whether a Copyright Was Renewed for more details).
But if the intended exploitation of the work includes publication (or distribution of derivative work, such as a film based on a book protected by copyright) outside the U.S., the terms of copyright around the world must be considered. If the author has been dead more than 70 years, the work is in the public domain in most, but not all, countries. Some works are covered by copyright in Spain for 80 years after the author's death.
In 1998 the length of a copyright in the United States was increased by 20 years under the The Copyright Term Extension Act.  This legislation was strongly promoted by corporations which had valuable copyrights which would otherwise would have expired, and has been the subject of substantial criticism on this point.
As a curiosity, the famous work Peter Pan, or The Boy Who Wouldn't Grow Up has a complex  and disputed  story of copyright expiry.

## Typefaces
In the United States, the Copyright Office maintains that typeface designs are not covered by copyright, and it will not accept applications for their registration.  See 37. C.F.R.  202.1(e). However, if a design is novel and "non-obvious," it may be covered by design patent.  See, for example, U.S. Des. Patent No. 289,773, May 12, 1987), Charles A. Bigelow and Kris A. Holmes, inventors. Germany (in 1981) passed a special extension (Schriftzeichengesetz) to the design patent law (Geschmacksmustergesetz) for protecting them. This permits typefaces being registered as designs in Germany, too.
The United Kingdom (in 1989) has passed a law making typeface designs copyrightable. The British law also applies to designs produced before 1989.

## Accessible Copies
It is legal in several countries including Great Britain and the USA to produce alternative versions (for example, in large print or braille) of a copyrighted work to provide improved access to a work for blind and visually impaired persons without permission from the copyright holder.