Before the Book there was the Text, and before the Text there was the Word, and before the Word there was the Thought.

Homer, or another bard, or maybe all of them, wrote a book. It came not on paper (or even vellum) but on the air. It was a book just the same.

Let's work our way up. It's a straight line. However, it's also another straight line that crosses in at least one place, and maybe more than two. As follows:

So far, so good. We're covered half the page and we haven't yet had to say anything about what the physical instantiation of the book actually is. In fact, the whole idea of e-books is that that physical instance is not the most important part of any book. You knew that already.

Let's consider some more lines, through the physical plane. (Oh, speak to us, O Spirits of the metaphysical plane. Oh, OK, we'll talk about books.)

Here we go again:

Let's try it again for an e-book:

I think we're on to something here.