A Crossroads game book, set in the world of Xanth. Alister wants a favor from Good Magician Humfrey. The only way to obtain it is to perform a service for the crotchety old gnome. Humfrey wants the missing volumes of the Encyclopedia of Xanth, a magically complete gazetteer of the land - and he will only settle for the whole set. Alister must set out, risking the perils of Xanth, with only his wits, his magical talent, and his rock hound Marbles to help him.