The Expanded Books Project was an undertaking at The Voyager Company during 1991, that investigated ideas on how a book could be presented on a computer screen in a way that would be both familiar and useful to regular book readers. A lot of time was spent thinking about font choice, font size, line spacing, margin notes, book marks, and so on.

Much of the original impetus for the project, however, dated back a year earlier to a small meeting on digital books that Voyager sponsored on Bloomsday, 1990, attended by various pioneering multimedia and hypertext experts. At this meeting, the consensus emerged that, to overcome the relative inconvenience of being tied to a low-resolution and cumbersome digital display, digital books would have to offer "added value." When Voyager developed the Expanded Books, it took this advice to heart.

The actual programming for the initial products happened over a relatively short period, between October and December 1991, with the first three book titles being released at MacWorld San Francisco, January 1992. Those first titles were The Complete Hitch Hiker's Guide to the Galaxy, The Complete Annotated Alice, and Jurassic Park. These books and their successors relied upon a "book engine" that provided a simple but powerful feature set: various convenient and simple search methods, the ability to switch between large print and normal print versions, various unobtrusive navigation tools (such as, for example, a chapter menu that dropped down from the chapter heading on each "page"), a margin area on each page in which readers could write notes, and, of course, interactive annotations. For example, Jurassic Park featured dinosaur illustrations that included dinosaur sounds based upon descriptions in the text; The Annotated Alice provided pop-up annotations derived from both editions of Martin Gardner's work.

The product range was not definitely to be called "Expanded Books". One other favored contender was "Power Books", but that idea died when Voyager was told that the about-to-be-released notebooks from Apple were to be called PowerBooks. Hence the original project name became the product name.

Between February 1992 and August 1992, Voyager created The Expanded Books Toolkit, which allowed authors to create their own Expanded Books. Voyager themselves went on to produce over 60 books as Expanded Books, and the underlying software was also used in CD-ROMs such as A Hard Day's Night, Salt of the Earth, and Macbeth.

All programming for the Expanded Books and Toolkit was in HyperCard, with the exception of a few XCMDs and strings stored as resources.