The World's Worst Psychopaths: The Most Depraved Killers In History

Often, the term 'psychopath' tends to be equated with violent and deranged criminality, but true psychopaths are very different from the way they are portrayed in film or on television. They are aware of the difference between right and wrong: they simply choose to ignore anything that prevents them getting what they want.

Real-life psychopaths are not 'mad' but 'bad', but they appear on the surface to be entirely 'normal'. One of the pioneers of the modern research effort was Dr. Robert Har...