I assume what you're thinking of is the codex as opposed to, say, a scroll or tablet. Although the Wikipedia article seems to suggest otherwise, the old Orientalist Bernard Lewis attributes the codex to the ancient Persians:

'We are on stronger ground in ascribing to Persians - and here we come back to the theme of cultural history - the book, that is the book in the form of the codex. The Greco-Roman world used scrolls, and so did much of the ancient Middle East. The codex, stitched and bound in the form we now know as a book, seems to have originated in Iran.' (Bernard Lewis, From Babel to Dragomans: Interpreting the Middle East, p. 49)