Secularism, the belief that religion should not be part of the affairs of the state, is an increasingly divisive topic. More than ever before, it is debated and criticized, as secular republics such as India and France face challenges from the resurgence of religious identity politics; while religious states like those of the Arab world enter into conflict with insurgent secularists. Andrew Copson tells the story of secularism from its origins in Europe and Asia to today. Throughout, he considers secularism's role in some of the most contentious political and legal issues of our time: blasphemy, apostasy, religious persecution, religious schools, and freedom of belief and thought.