With the Anglo-American air war against Germany going badly in 1943, U.S. General Hap Arnold had an idea: shuttle bombing. Instead of American bombers dropping their payloads over Western Europe and returning to base in Britain, why not keep going—to the Soviet Union? Maybe our communist ally would allow American planes to refuel, reload and bomb Germany again on the way back to Britain? Stalin distrusted the idea of foreign troops on his soil but relented. In the first full-on documentation of this missing page of the war, Harvard’s Serhii Plokhy tells a fascinating story of a dozen dangerous missions flown from decrepit facilities in Ukraine. Spied on and harassed by the Soviets, the mission accomplished relatively little except to serve as a barometer for increasing tensions between the U.S. and the U.S.S.R.