Columbia University Professor Dr. Michael Stone is forensic psychiatrist and personality expert who developed "The Stone Scale," also known as the “Gradations of Evil.” The scale uses forensic analysis to score serial killers and psychopaths between 1 and 22, indicating just how evil each individual is. In this series, he deconstructs the wicked deeds and psychological makeup of the world’s most notorious predators, using the results to count down the most evil human beings of our time.