Lycanthropy is a mysterious subject. Ancient belief in lycanthropy was widespread, and it still exists in parts of the world. Literatures all over the world have tales of men changing to animals. Werewolves are often related to demons, devils, blood and full moon. In the Middle Ages the church condemned lycanthropy as a form of sorcery and often ruthlessly punished the supposed offenders. In this classic study, Sabine Baring-Gould, a historian, examines the literature about this matter in a serious perspective.