Book

Yes, you eat the Book.
The Book is technically a Food item that replaces all models/props_lab/binder* on any map. It can also be obtained as the lowest tier drop from the Pukepus. The Book can be enhanced into the IKEA Catalog. You can only consume the Book if you have the Wizard Attribute and the Scholar Skill. Otherwise, it will knock you down for 10 seconds and give 0 food power. With Wizard and Scholar, each Book consumed increases your Intelligence by 1. The Intelligence bonus only applies up to 10 books, or 20 if you have Memory of the Pious.