Madame Fourcade's Secret War by Lynne Olson
In 1941, a 30-yr old wealthy and socially-connected woman became leader of a resistance network called Alliance, which became the most successful underground intelligence network in France. By the end of the war, Alliance included about 3000 agents, 20 percent of them women. Throughout the war, this group provided massive amounts of critical information to MI6, including German troop movements, u-boat schedules, and the existence of V1 and V2 facilities at Preenemunde. Amazingly, right before D-Day, one of her agents produced a 55-foot long map of the beaches of Normandy that included details of every German gun placement and fortification. Fourcade managed this network while being constantly pursued by the Gestapo, and being captured and escaping. It's not particularly well-written, and is pretty dry in parts, but a good read about an amazing woman.