In the summer of 1941, Harry Hopkins, Franklin Roosevelt's trusted advisor, arrived in Moscow to assess whether the U.S. should send aid to Russia as it had to Britain. Unofficially, he was there to determine whether Josef Stalin—the man who had killed over six million Ukrainians during the 1930s—was worth saving. In this sweeping narrative, John Kelly chronicles the turbulent wartime relationship between Roosevelt, Churchill, and Stalin, as well as the military commanders of their nations. Faced with the greatest challenge of the century, the Allies eventually triumphed, but at what cost?