Digital books

What is a book, anyway? If players of the brooding computer game Dear Esther can consume a full-blown ghost story simply by wandering at will through a deserted island in Scotland's Hebrides (finding fragments of letters, music, and clues as they walk), shouldn't that be called a book? Critics can't seem to agree on a name for this new genre reflected in Inanimate Alice: multimedia online novels, ebooks, touchable TV, paratext, or technotext have all been used.