"The triumphant true story of the young women who helped to devise the winning strategy that defeated Nazi U-boats and delivered a decisive victory in the Battle of the Atlantic." -- From book jacket. "By 1941, Winston Churchill had come to believe that the outcome of World War II rested on the battle for the Atlantic. A grand strategy game was devised by Captain Gilbert Roberts and a group of ten Wrens (members of the Women's Royal Naval Service)...