When American physicist Ted Hall joined the ultra-secret Manhattan Project in 1943, he became the youngest scientist working on the development of the plutonium bomb. He was so shocked by the results that he decided to hand over atomic secrets to the Soviet Union. He later described it as an act of compassion. It was 1951, at the height of the Cold War, and Hall’s act was tantamount to suicide—the nuclear spies Julius and Ethel Rosenberg were executed for less serious crimes. As if by some miracle, however, Ted and his wife Joan managed to stay out of the hands of the FBI.Now nearing the end of her life, Joan Hall looks back on those years and talks about her love for the man who perhaps saved the world from a catastrophe. A Compassionate Spy is the portrait of an intensely civilized and modest couple in a barbaric time. “If you think the United States is not a good place now,” says Joan, “it was worse then.”