This shocking but thought-provoking analysis of some of the world's worst serial killers looks at their early years in an effort to understand why they did what they did. Why do human beings turn into killing machines? Are they born to kill or are they trained to kill? The authors have spoken with killers all over the world in a quest to understand what makes them go bad. It results in the minds of the most destructive individuals on the planet revealed in stomach-churning detail.