The Adventure Time Encyclopedia: Perhaps the most dangerous book in history, seeminly a guidebook to the Land of Ooo, but in fact designed to drive the reader mad.
The Enchiridion: The Adventure Time tome for heroes whose hearts are righteous, containing both true and false information from the future and past ...
Marcy's Super Secret Scrapbook: This book holds the secrets of the Lord of Evil's daughter, Marceline the Vampire Queen.