Jeremy C writes below, “Doesn’t having a uniform page layout for all the books on the device focus your attention, not on the layout/design, but on the content?” Great question. I think the answer depends on how we make the distinction between form or presentation and content. It has become fashionable in some circles to deny the distinction, to insist that form and content are one — but that strikes me as an over-reaction to simplistic attempts to make an absolute distinction between the two.
The fact of the matter is that reading the brilliant Pevear-Volokhonsky translation of War and Peace on a Kindle and reading it in the lovely Knopf hardcover edition are distinctively different experiences — and yet if one person reads the Kindle version and one reads the Knopf hardcover we are fully justified in saying that both of them have read the same book. (At least insofar as we are willing to say that two different people ever read “the same book.”) We can tell this by applying a version of the Turing test or Chinese room experiment: in any imaginable conversation with readers of War and Peace, it would be impossible to determine which of then had read a printed book and which had read via some electronic medium.
So there is a sense in which the content of the book is distinct from its form. And yet there is also a sense — a subtler, harder to specify sense — in which reading experiences vary according to medium, form, presentation. I think we’re really at the early stages of trying to understand this kind of thing.