All documents consist of content, structure and a user interface.
The main task of the author is to provide the content, however, depending on the availability of support staff and the author's skills, the author may be called upon to help develop the document structure and user interface. In the case of a traditional paper-based book, structure and user interface conventions have been established over the past hundred years. Thus the author can rely on help from editors, publishers and printers with these details of document production. For hypertext documents the situation is more complex. A linear structure is generally not appropriate, hence the author must deal with the structural aspects of the document.