It needs to be repeated that books are much more than merely vehicles for text. Awareness of the way a book is created, the materials of which it is made, flipping through the volume to see how it is arranged, the intended readership, the clues of the previous ownership and use, and potential problems in its conservation - all these become almost instinctive for experienced readers. (For rare-book custodians, such things as smelling a volume or shaking a leaf to hear the rattle provide further "forensic" information.) This is like an extension to the metadata (such as a book's Dewey class number), which is still largely absent from e-books.