Viktor Bout was a warlord's warlord, according to MI6, the US National Security Council and the CIA--a terrorist facilitator, and the world's most prolific arms dealer. They tracked him everywhere, smuggling weapons from North Korea and the former Soviet Union into the world's bloodiest conflict zones, from Liberia to Afghanistan. Intelligence services called him a secret KGB asset; the White House, the most dangerous man in the world. But Bout strenuously...