The world’s leading psychiatric authority on demonic possession delves into the hidden world of exorcisms and his own transformation from cynic to believer over the course of his twenty-five-year career. Successful New York psychiatrist Richard Gallagher was skeptical yet intrigued when a hard-nosed, no-nonsense Catholic priest asked him to examine a woman for a possible exorcism. Meeting her, Gallagher was astonished. The woman’s behavior defied logic. In an instant, she could pinpoint a person’s secret weaknesses. She knew how individuals she’d never known had died, including Gallagher’s own mother, who passed away after a lengthy battle with ovarian cancer. She...