Minecraft wiki entry for Book_and_Quill, associated text: The title of the book can be up to 16 characters long, and the player cannot paste into a title. A "workaround" for the 16-character limitation is to manually rename the book at an anvil, which always costs 1 experience level. This can be done with either a written book or a book and quill – both versions will always display the changed name. If a custom name is removed from a written book, it will revert back to the title it was given during the signing process.