Apple sent Voyager a prototype PowerBook in spring, 1991. The form was very different than desktop computers, and immediately the Voyager team was imagining electronic books.
In October 1991 the first three Expanded Books were released, for $19.95 each: ‘Alice in Wonderland’, annnotated by Martin Gardner, Douglas Adams’ ‘Hitchhiker’s Guide to the Galaxy’ (an inevitable choice), and Michael Crichton’s ‘Jurassic Park’.
Expanded Books could be easily navigated, searched and annotated. Pages could be marked by dog-earing them. Passages could be hilighted. Support materials, activated by hypertext, added value.
Voyager Co. produced over 70 Expanded Books. In 1992, they made the Expanded Book Toolkit available. The format was used, by many academics and other authors, for much of the 1990s.
2012 Apple Released iBooks Author aka Hypercard in modern form.