King of Spies is the story of U.S. Air Force Major Donald Nichols, an intelligence agent who operated in Korea for 11 secret years with his own army of spies, his own base, and his own murderous rules. The book sheds new and disturbing light on the U.S. role in the Korean War. More importantly, it explains—at a time when North Korea is threatening the U.S. with long-range nuclear missiles—the origins of an intractable foreign policy mess.

In 1946, master sergeant Nichols was repairing jeeps on the sleepy island of Guam when he caught the eye of recruiters from the army’s Counter Intelligence Corps. After just three months’ training, he was sent to Korea, then a backwater beneath the radar of MacArthur’s Pacific Command. Though he lacked the pedigree of most U.S. spies—Nichols was a 7th grade dropout—he quickly became a black ops phenomenon. He insinuated himself into the affections of America’s chosen puppet in South Korea, President Syngman Rhee, and became a pivotal player in the Korean War, warning months in advance about the North Korean invasion, breaking enemy codes, and identifying most of the targets destroyed by American bombs in North Korea.

But Nichols’s triumphs had a dark side. His closeness to Rhee meant that he witnessed—and did nothing to stop or even report—the slaughter of tens of thousands of South Korean civilians in anticommunist purges. Immersed in a world of torture and beheadings, he  recruited agents from refugee camps and prisons, sending many to their deaths on reckless missions.

King of Spies traces Nichols’s unlikely rise and tragic ruin, from his birth in an operatically dysfunctional family in New Jersey to his sordid postwar decline, which began when the U.S. military sacked him in Korea, sent him to an air force psych ward in Florida, and subjected him—against his will—to months of electroshock therapy. King of Spies  reminds us that the some of the darkest sins of the Vietnam War—and many other conflicts that followed—were first committed in Korea.