They were two of the most evil dictators of all time. Each of them was responsible for the murders of millions of people, most often with unspeakable cruelty. Yet they had no hesitation or remorse. Why? What drove them to inflict the atrocities of torture and mass murder, while creating virtual secular religions to themselves? Were they born evil, or did something in their lives make them evil, dispassionate murderers? Discussion of their developmental years and adult lives give strong evidence about "nature and nurture." The world would be different today if each of them had succeeded in their early ambitions: Hitler as an artist, Stalin as a priest and poet. What drove them through spiraling events of world wars to do what they did and become among the most feared people in history?