The cold war was near absolute zero, the Korean War was raging, and the West could almost hear the Soviet tanks gunning their engines on the other side of the Iron Curtain. The U.S. and its European allies were determined not to be caught as unprepared as they had been when the Nazis invaded. So in the early 1950s they began training "stay behind" networks of volunteers. If the Soviet army rolled west, the groups were to gather intelligence, open escape routes and form resistance movements.
Originally advised and financed by the U.S. Central Intelligence Agency, many of the units and...