The concept of evil is universal, ancient and ever present today. The biblical book of Genesis clearly defines it when Cain kills his brother Abel out of jealousy. Evil is a choice to make another suffer. As long as human beings have walked, evil has been close by. CONFRONTING EVIL by Bill O'Reilly and Josh Hammer recounts the deeds of the worst people in history: Genghis Khan. The Roman Emperor Caligula. Henry VIII. The collective evil of the 19th-century slave traders and the 20th-century robber barons. Stalin. Hitler. Mao. The Ayatollah Khomeini. Putin. The Mexican drug cartels. Collectively, these warlords, tyrants, businessmen and criminals are directly responsible for the death and misery of hundreds of millions of people.