Everything you need to understand or teach Wicked (novel) by Gregory Maguire.
Wicked is a revision to the Land of Oz, focusing on the life and times of the Wicked Witch of the West. This novel turns the story of the Wicked Witch on its head, exploring the social and political world of Oz and revealing its harsh realities. The Witch's story is one in which cruelty is inflicted upon her, yet surprising friendships persist throughout. The Witch struggles her entire life with the existence of fate, the soul, and the existence of evil.