Legion
William Peter Blatty
 The story opens with the discovery of a twelve-year-old boy who has been murdered and crucified on a pair of rowing oars. Kinderman already sees that the boy is mutilated in a way identical to the victims of a serial killer known as the Gemini Killer, who was apparently shot to death by police twelve years previously while climbing the Golden Gate Bridge in San Francisco. A priest is later murdered in a confessional, once again bearing the mutilations distinctive of the apparently deceased killer. The fingerprints at the two crime scenes differ, however. Further victims soon follow, including one of Kinderman's friends, another priest, who is slain in a hospital, his body drained of blood before being decapitated. Yet again the Gemini Killer's mutilations are present. Investigations lead Kinderman to the psychiatric wing of the hospital where his friend was slain. Here he finds a number of suspects: * Dr. Freeman Temple - a psychiatrist who has a dismissive and even contemptuous attitude towards his patients. * Dr. Vincent Amfortas - another doctor at the hospital. He is very mysterious and not very talkative, and is seemingly apathetic towards everything since the recent death of his wife. * Patients - there are a number of elderly people at the hospital suffering from senile dementia. The fingerprints of different senile patients are found at murder scenes, but interviews with the patients make it clear they are seemingly incapable of carrying out the elaborate killings and mutilations. * Tommy Sunlight - a mysterious patient, found wandering aimlessly eleven years ago dressed as a priest, who brags of being the Gemini Killer reincarnated and who claims to have carried out the recent murders, even though he logically could not have done so, being secured in a locked cell in a straitjacket. At one point he claims the doctors and nurses let him out to kill. He also looks identical to Damien Karras, a priest who supposedly died in The Exorcist by falling down a flight of stairs. * James Vennamun - the actual Gemini Killer himself. His body was never found, suggesting he may have survived and is resuming his crimes. In the end, the implication is that the Gemini Killer possessed the body of Damien Karras and spent many years trying to gain control of the body, during which time Karras was held in a mental hospital. He lacked any identification and was nicknamed Sunlight because he sat in the sun's rays as it passed through the window of his cell. Upon finally gaining control of Karras' body, the Gemini occasionally left it to possess the bodies of the patients suffering from senile dementia, and as they were in an open ward with access to the outside world, he could use them to go forth and commit murders. This is why the fingerprints of several senility patients were found at the crime scenes; their bodies carried out the murders but the Gemini Killer was in control of them. The Gemini's motive originally was to shame his father, a preacher, whom he hated. When his father dies of natural causes the Gemini Killer feels his mission is over and he has no reason to remain in possession of Karras' body. Feeling compelled to explain everything to Kinderman, he summons the detective, explains all of this, successfully demands that Kinderman tells him he believes that he (Sunlight) really is the Gemini Killer, and then effectively wills himself to die from heart failure. Dr. Temple suffers a stroke and ends up mentally disabled. Dr. Amfortas dies in an accident (although he was terminally ill anyway, suffering from a disease he refused to treat so he could join his deceased wife). The final chapter of the novel, an epilogue, has Kinderman at a burger-bar with his faithful partner, Atkins. Kinderman explains to Atkins his thoughts and musings of the whole case and how it relates to his problem of the concept of evil. Kinderman ends by concluding that he believes the Big Bang was Lucifer falling from heaven, and that the entire Universe, including humanity, are the broken parts of Lucifer, and that evolution is the process of Lucifer putting himself together back into an angel.