Castle of Wizardry (Belgariad Series #4)

The Belgariad is an epic fantasy of immense scope, telling the tale of struggles between ancient Gods and mighty Kings, and of men in strange lands facing fated events, all bound by a prophecy that must be fulfilled.

It all began with the theft of the Orb that protected the West from the evil God Torak. Before that, Garion had been a simple farm boy. Afterward, he discovered he's a sorcerer. Now, at last, the Orb has been regained & the quest nears its end. Of course, the questors must still escape from a crumbling enemy fortress, flee across a desert filled with Murgo soldiers, avoid the Grolim Hierarchs seeking to destroy them with dark magic. After that, Garion feels assured his part would be finished. But the prophecy still holds several surprises for Garion, & for the Imperial Princess Ce'Nedra.