Far from sweeping away popular superstitions about Satan and witchcraft, the Reformation and later the religious crisis culminating in the Civil Wars of 1637-1653 opened up a whole new field of ideas about the Father of Lies and his disciples. Out of these great social and religious changes came a distinctly Protestant and English view of the devil. This text traces religious, popular and political uses of Satan and witchcraft in early modern England, showing how for Protestant, and later Puritan, believers, Satan could be used for both anti-Catholic and anti-monarchist propaganda in a form of selective assimilation between folklore and theology. Diabolical possession, belief in the devil as a kind of supernatural avenger who was God's agent in punishing evil-doers, exorcisms and witch trials were an essential part of popular culture in early modern England. The skill with which Puritan ministers and Parliamentarians exploited and used these beliefs played a large part in the spread of popular support for the ideas of the Reformation and the Parliamentarian cause. This text advances controversial conclusions, in particular on the subject of modern-day beliefs about the nature of the devil. Using many records of witch trials and accounts of exorcisms and possessions, the author brings to life a range of popular and learned beliefs which have gone largely unexplored and which add to our understanding of the cultural and religious legacy of the Reformation.