In a far-future world of wizards and walled cities, Cascor is a bitter cashiered policeman who has built a new career as a freelance discriminator who occasionally dabbles in magic and hopes the wizards' Guild never finds out.

This collection brings together all the Cascor stories, including four that began with the discriminator as a supporting character in the series about Raffalon the unlucky thief. It includes three more that ran in The Magazine of Fantasy & Science Fiction, plus two original novelettes and a short novella about the sorceress Margolyam, who became one of Cascor's strange "family" of operatives.