Physical pain ranks as one of the great evils of human life, not far behind death. Yet, religious individuals and groups around the world and throughout history have inflicted pain on themselves and on others in pursuit of religious goals. Despite this, no broad explanation for the uses of pain has emerged, and this book seeks to remedy this lack. Glucklich shows that a ritually controlled regimen of pain can produce a transformation of consciousness in which personal identity gives way to identification with God, Truth, or other spiritual ideals. This phenomenon is explored in many cultural and historical contexts, including rituals of possession and exorcism, rites of passage, and the tortures of the Inquisition. Glucklich also shows how the modern invention of anæsthesia transformed our perception of pain and undermined the idea that pain can be good. This book helps us to understand "sacred pain" from the perspective of its practitioners, opening a window onto a mysterious world of experience.