True evil seems easy to recognize: the killing of innocent children; assigning whole populations to death by gassing, or napalm, or aerial bombing. These acts go beyond the criminal, the mean, the bad. But what is the psychology of evil-doers? Are they monsters among us — just like the rest of us, with one screw a little loose, or are they radically unlike us? John and Ken probe the evil mind with Simon Baron Cohen from Cambridge University, author of The Science of Evil: On Empathy and the Origins of Cruelty.