The prologue relates the events of an actual exorcism -- we learn the details of that one later -- then the first chapter opens with Fr. Gary's arrival in Rome. Throughout the book we hear about Fr. Gary's past: his childhood, his vocation, the accident that nearly killed him, and how he wound up in Rome taking classes about exorcism.
The book includes a map of Rome in the vicinity of the Vatican, and interesting details about what life is like there. Historical facts about demons, possession, and exorcism are sprinkled throughout.
The first third or so of the book covers how exorcism has been handled in the Church, focusing on how belief in the person of Satan and demons almost got philosophized out of existence in the wake of modern medicine and Vatican II. Formal training in exorcism has only resumed within the last decade, as increasing numbers of people come to their parish priests, seeking help, and the priests have no idea what to do or who to turn to.
The most interesting part is when Fr. Gary starts to apprentice with an actual exorcist, who is practicing in Rome. What he witnesses ranges from mildly weird to downright horrifying, and it turns out that exorcism is much more complicated than movies have led us to believe.
Eventually Fr. Gary's training ends, and he's sent back home, as his diocese's official exorcist, nervous about having never performed the ritual himself. After a few cases of the mildly-strange variety, he comes up against a case of real, blatant possession. And the prayers work -- he can help.
The book is told from a Catholic perspective, naturally, since it follows a Catholic priest and his training at the Vatican. Other belief systems are incorporated too -- the belief in demonic possession and curses is nearly universal across all cultures -- and some effort is made to come up with non-supernatural explanations. But it is obvious that both Fr. Gary and the author cannot make themselves believe that there is any natural cause behind what they have seen.
Overall, a fascinating book. Highly recommended.
(review originally posted on Amazon)