This chapter argues that witchcraft pamphlets from across the entire period of witchcraft prosecutions demonstrate a continuing connection between witchcraft and the Devil in the minds of contemporaries. It explores the changing nature of beliefs about the Devil during the fifteenth, sixteenth, seventeenth and eighteenth centuries. The chapter highlights the growing fear of the Devil that coincided with the Protestant Reformation in England and explores the increased emphasis on the Devil as a source of mental temptations. It focuses on the different concepts of the Devil that appeared in early modern English witchcraft pamphlets and demonstrates how these narratives incorporated an ambiguous set of beliefs about the Devil. The understanding of the Devil promoted by Protestant theologians never entirely triumphed in early modern England. Contemporary authors make it very clear that they believed that the Devil's increasing power in the world was directly related to increasing numbers of witches.