Sourcery is the fifth Discworld novel by Terry Pratchett,. On the Discworld, sourcerers – wizards who are sources of magic, and thus immensely more powerful than normal wizards – were the main cause of the great mage wars that left areas of the disc uninhabitable. The first few pages of the novel deal with a sourcerer's father who cheats death. The rest of the novel deals with the sourcerer's plan to have wizards rule the Discworld, and the efforts of a small group.