Everyone has felt the urge to kill. Most people don't kill. Some people do. Dorothy Otnow Lewis, a psychiatrist and an internationally recognized expert on violence, has spent the last quarter century studying the differences between those who do and those who don't. Among the murderers she has examined are the notorious killers Ted Bundy, Arthur Shawcross, and Mark David Chapman, the man who shot John Lennon. Now, she shares her groundbreaking discoveries - and the chilling encounters that led to them. Guilty by Reason of Insanity is the true story of Dr. Lewis's search to understand those who kill. The cases revealed here clearly illustrate how the disparate elements of brain damage, paranoia, and family brutality combine to create a killer.