When he first heard about a Vatican-sponsored course on exorcism for priests, journalist Matt Baglio was intrigued by the idea of this ancient ritual taking place in the modern world. In his new book The Rite, Baglio follows American priest Father Gary — sent to Rome to train as an exorcist — and his apprenticeship with Father Carmine. Baglio talked to TIME about belief, skeptical priests, and the particulars of the exorcism ritual
