A mostly unsuccessful attempt to fathom the psyche of a doctor who claimed that voices often directed his bizarre behavior. Ablow, a columnist for the Washington Post and a practicing psychiatrist in Lynn, Mass., examines John Kappler's troubled life and tries to peer into his tortured mind. He opens this account with the day that Kappler, a truly unsympathetic character and a terribly dangerous man, drove his car off a parkway in Boston and aimed it carefully at two people on a pedestrian path. One of them, a psychiatrist friend of the author's, was killed. Ablow then turns to Kappler's childhood, looking for clues and speculating about the causes of his instability, anger, and destructiveness. He traces Kappler's spotty medical career (he was a freelance anesthesiologist, working out of some 50 hospitals in the Los Angeles area) and his frequent nervous breakdowns. Over the years Kappler received more than a dozen different diagnoses from psychiatrists and sporadically took numerous medications, including antipsychotics. Though he seems to have received little real help, it is not clear that he would accept any. Despite his problems and the threat his erratic behavior posed to patients, he continued practicing medicine until 1985, when he was accused of turning off a patient's life support system. Although the charges were later dismissed, Kappler, thoroughly disgraced, finally retired. The last portion of the book focuses on the murder trial in Boston, at which the central issue was whether Kappler was accountable for his actions or not guilty by reason of insanity. The jury found him guilty, but Ablow argues that he should more properly be seen as a victim -- both of mental illness and of psychiatry's failure to help him. Ablow speculates and opines freely, but Kappler, who refused to be interviewed, remains a dark mystery.