What is a Book?
"Bookness" is a term coined by Phillip Smith in the 1970's used to describe the qualities that have to do with a book. In its simplest form, a book is a series of planes bound in a fixed or variable sequence. It is bound using a hinging mechanism, support, or container. For the most part this term should not be applied to pre-codex carriers of text or anything on a single planar surface.
Text other than a book.
Much of the confusion arises with the association of book and text. The text is the visual or verbal content of the book, not the book itself. A text can be anywhere, on a CD, a pyramid, or a TV screen. Without text, no one would describe these objects as books, but a book, even without a text, is still a book.
A textless book.
As Phillip Smith says: "The book-makers art should be distinguished from the art-maker's book. The book is generally thought of as a compact convenietly portable object (although there can be giant books, made of any material). The book as a book, has multiple planes because all the text or material it contains would be too unwieldly in a single planar form. There are book-like objects or appearances and object-like books, but that is a different story."