In April 1967, twenty-year-old Doug Hegdahl was knocked overboard from a U.S. Navy cruiser in the Gulf of Tonkin. Initially believed to be a special ops commando, he was turned over to North Vietnamese who beat him and then turned him over to the prison known as the Hanoi Hilton, where Hegdahl maintained a ruse of being a country bumpkin who couldn’t read or write. The North Vietnamese called him “The Incredibly Stupid One,” and guards paid no attention to Hegdahl as he proceeded to memorize information about more than 250 prisoners, which he memorized to the tune of “Old MacDonald Had a Farm.” Offered release in the summer of 1969, Hegdahl balked—the POW code stipulated that prisoners should be released in the order of capture—but was ordered to accept so that he could provide his information to the American military.

In a vividly written book based on archival research, personal interviews, and the author’s own experiences in the Vietnam War, Marc Leepson tells the story of this most unique of American military heroes. Most of the prisoners in the Hanoi Hilton were pilots or navigators—such as John McCain and James Stockdale—and Hegdahl was the only non-officer, the lowest-ranking person in the prison. He was never properly recognized or decorated for his extraordinary efforts after the war, and his story has never been told, except briefly in books like John McCain’s Faith of My Fathers. Hegdahl’s is a story of survival, not only his own, but that of the hundreds of American POWs he helped ensure.