Sourcery : a novel of Discworld
When last seen, the singularly inept wizard Rincewind had fallen off the edge of the world. Now, magically, he's turned up again, and this time he's brought the luggage. But once upon a time, there was an eighth son of an eighth son who was a wizard. Then said wizard had seven sons. And then he had an eighth son -- a wizard squared who was a source of magic: a sorcerer
Print Book, English, 2001
HarperTorch, New York, 2001