The sacred calls that summon believers are the focus of this study of religion and power in Fez, Morocco. Focusing on how dissemination of the call through mass media has transformed understandings of piety and authority, Emilio Spadola details the new importance of once–marginal Sufi practices such as spirit trance and exorcism for ordinary believers, the state, and Islamist movements. The Calls of Islam offers new ethnographic perspectives on ritual, performance, and media in the Muslim world.