Handbook of Exorcism

Exorcism is the religious or spiritual practice of evicting demons or other spiritual entities from a person, or an area, that are believed to be possessed. Depending on the spiritual beliefs of the exorcist, this may be done by causing the entity to swear an oath, performing an elaborate ritual, or simply by commanding it to depart in the name of a higher power. The practice is ancient and part of the belief system of many cultures and religions. Requested and performed exorcism began to decline in the United States by the 18th century and occurred rarely until the latter half of the 20th century when the public saw a sharp rise due to the media attention exorcisms were getting. There was "a 50% increase in the number of exorcisms performed between the early 1960s and the mid-1970s".