The Exorcist Effect examines the relationship between horror films and religious culture, focusing on the period from 1968 to the present. Films like Rosemary's Baby (1968), The Exorcist (1973), and The Omen (1976) claimed to be based on actual events, religious traditions, and Biblical texts. These films inspired subsequent beliefs and experiences, which became the basis for yet more horror films. This book draws on archival research to shed new light on such figures as Ed and Lorraine Warren and Malachi Martin, who inserted themselves into this cycle. It also incorporates interviews with horror authors, film writers, and paranormal investigators.