The birth of psychiatry in the early nineteenth-century fundamentally changed how madness was categorized and understood. A century on, their conceptions of mental illness continue to influence our views today. Beliefs and behavior were divided up into the pathological and the healthy. The influence of religion and the supernatural became significant measures of insanity in individuals, countries, and cultures. Psychiatrists not only thought they could transform society in the industrial age but also explain the many strange beliefs expressed in the distant past. Troubled by Faith explores these ideas about the supernatural across society through the prism of medical history. It is a story of how people continued to make sense of the world in supernatural terms, and how belief came to be a medical issue. This cannot be done without exploring the lives of those who found themselves in asylums because of their belief in ghosts, witches, angels, devils, and fairies, or because they thought themselves in divine communication or were haunted by modern technology. The beliefs expressed by asylum patients were not just an expression of their individual mental health, but also provide a unique reflection of society at the time—a world still steeped in the ideas and imagery of folklore and faith in a fast-changing world.