In all my years growing up surrounded by examples, I never once gave thought to precisely how the book was defined. It would have seemed like a silly question, really. It’s only in relatively recent times I have come to the realisation that, to paraphrase a classic television commercial from my childhood, books ain’t books. By accident of history, we have applied the same word to pop-up illustrations for children, lavish art and architecture hardcovers, compendiums of home cooking recipes, telephone directories, multi-volume encyclopaedias, historically significant works of literature and poetry, and fun and exciting works of entertainment and pop culture. What we call a ‘book’ has always been loosely inclusive. The only common element to these kinds of content is the object through which they’re distributed: paper, ink, thread, glue.
It was a definition of convenience. After all, the magic of a book has never resided in its ink and paper (though they aided greatly in its portability). No one becomes a lifelong reader because of their love of offset printing. Each of the kinds of content listed above fulfilled a different need: some were served well by ink and paper, others perhaps not so much.