Many readers will be at least vaguely familiar with a novel called The Exorcist, or with the movie based on it. The author, William Peter Blatty, based his story loosely on a now legendary series of events said to have taken place in St. Louis, Missouri some fifty years ago. Exorcism has long been available to Roman catholics as a ritual designed to free individuals thought to be possessed and tormented by evil spirits. Church authorities have very rarely given permission to perform exorcisms and only after extensive psychiatric and medical consultation. The local bishop appoints a priest known for his sanctity, sanity, and personal strength to act as the principal ritual specialist. That exorcist then prepares to use a set ritual and to subject himself to whatever spiritual discipline may be necessary to withstand the rigors of the experience. Peculiar and frightening occurrences are said to accompany exorcisms. Father William Bowdern, the Jesuit priest who performed the St. Louis exorcism, refused ever to speak of the experience in public, except to affirm that he did indeed believe in the existence of the devil.

According to the New Testament, Jesus and his Apostles performed a number of exorcisms, a practice not altogether rare among Jews and pagans of the time. His actions are the ultimate sanction for the practice in Roman Catholicism. During medieval and even into early modern times, some people were executed as witches because they proved impervious to exorcism. Until about thirty years ago, Roman Catholic practice continued to confer on candidates to the priesthood the “minor order” or office of exorcist. Exorcism remains relatively common among some Christian denominations, especially Pentecostal or Charismatic groups. Leaders of worship might perform an exorcism as one among many manifestations of the Spirit, by prayer and touch intended to free the one possessed. Here exorcism is generally a very brief part of the larger ritual. A much-simplified form of exorcism remains a brief preliminary part of the ritual of baptism in many churches.