What is the theme in Sourcery by Terry Pratchett?

The desire for power is a major theme in this story. Sourcery is a book that has two different places where the desire for power affects the characters. The first few pages of the story tells about Ipslore the Red's last few moments alive. As he stands there talking to Death, it is easy for the reader to see that Ipslore was unable to get the power and respect he wanted in his own life. He tries to force his own desires for power, and ultimately revenge, upon his son. When Ipslore is talking to Death, he is reminded that he had seven sons before that wouldn't do what he asked them to do and eventually all seven of them left.