The sixth edition of the Concise Oxford Dictionary (Oxford University Press, 1964, 1976) defines a book as "n.1. Portable written or printed work filling a number of sheets fastened together, usu. with sheets sewn or pasted hinge-wise and enclosed in cover . . . ; literary composition that would fill such a set of sheets (or several) if printed . . . " [my italics].

Essentially, a book is a means of communication rather than a bound collection of printed material. It is only while we think of books as being physically embodied or realised in a certain way that we will think of electronic books or e-books as being virtual books. Once we take this new form of technology for granted, we will come to think of e-books simply as books, as real as any other kind.