In the first generation of speech, storage and transmission of information are both extragenetic; in the second generation of print, storage is extrasomatic; in the third generation of television, transmission is extrasomatic; in the fourth generation of hypermedia, to complete this typology, both storage and transmission are extrasomatic.

THE HYPERBOOK

      A hyperbook is created by organizing its content as a stack of cards, with buttons to link each card to related cards. This could be distributed as a floppy disc, which can be read by a computer loaded with the program in which it is written (let us say, for example, a Macintosh loaded with HyperCard). For those who do not have an appropriate computer and program to read this hyperdisc, the cards in the stack are simply printed out, spiral-bound along the top edge, and offered to the reader as a hyperbook. Instead of clicking icons to go instantly to related cards, the reader simply notes that there is related information on a certain card, and physically turns to this card.

Following are the major design features of a hyperbook which the author is currently creating (Gardiner, 1992):

1. The basic unit of the hyperbook is the 'card' - that is, a screenful of information - rather than the conventional page in a traditional book.
2. It consists of 'text' cards on the bottom and 'image' cards on the top.
3. The text cards have a link strip down the right-hand side, which may contain 'buttons' indicating links to other cards. The 'icon' on the button indicates the kind of information on the linked card, and the number below the button indicates its location.
4. The image cards have distinctive backgrounds reflecting the kind of information they contain: that is, quotations in balloons, lists of books on a bookshelf, etc.