They were for an event where the real Book of Truth was lost... Scribes at the Lyceaum collected them and gave out rewards, then at the end of the event, one book was determined to be the real one. Whoever turned in that book was immortalized in the halls under the Lyceaum. Since the real book was found - there is no official purpose for the remaining fake Book of Truth?s. You can maybe sell them to other players who are lower-end rare collectors for around 100k+, or keep them as decorations. Otherwise they do nothing.