The Book of Güd was a magical book that was the antithesis of the Book of E-Ville. It contained no words, only pictures, but ones that caused serenity that the foolish cannot see and the evil cannot stand up to, powerful enough to drain K'Z'K's power when he glanced at them. During the War of the Bug Squishers, the book was held in the Cave of Yffi, and Torg and Zoë were able to use it to defeat K'Z'K before returning to the present. It has not been seen since.
See also Book of E-Ville