Inspired by a bold nun, on nearly twenty occasions over the course of his ministry Martin Luther invoked her way of warding off the devil and the temptation to despair. I am a Christian, she would say to the Tempter, and Luther's admiration for her becomes an entre to the whole religious world of the middle ages and Luther's time. Schneider's fascinating journey goes in search, first, of the meaning that this story had for Luther and his theological world but then of the nun's identity and the whole role of the devil, guilt, sin, and temptation in the medieval worldview. Finall, Schneider turns to today and people's struggles with despair, sickness, addiction, and death. She shows the strange but undeniable pertinence of the whole idea of the devil, Christian community as a bulwark against evil, and how Luther's battles illumine our own.