"The 15th century is more than any other the century of the persecution of witches." So wrote Johan Huizinga in his book "Autumn of the Middle Ages". Although Huizinga was correct in his observation, modern readers have tended to focus on the more spectacular witch-hunts of the 16th and 17th centuries. Nevertheless, it was during the late Middle Ages that the full stereotype of demonic witchcraft developed in Europe, and this is the subject of this volume which places the Dominican theologian Johannes Nider at the centre of an emerging set of beliefs about diabolical sorcery and witchcraft in the 15th century. Nider alternately persecuted heretics and negotiated with them - a man who was by far the most important church authority to write on witchcraft in the early 15th century. Nider was a major source for the infamous "Malleus Maleficarum", or "Hammer of Witches" (1486), the manual of choice for witch-hunters in late medieval Europe. Nider's reputation rests squarely on his witchcraft writings, but in his own day he was better known as a leader of the reform movement within the Dominican order and as a writer of important tracts on numerous other aspects of late medieval religiosity, including heresy and lay piety. The book places Nider in this wider context, showing that for late medieval thinkers, witchcraft was one facet of a much larger crisis plaguing Christian society.