Early in the Great War, men left Britain's factories in droves to enlist. Struggling to keep up production, arsenals hired women to build the weapons the military urgently needed. "Be the Girl Behind the Man Behind the Gun," the recruitment posters beckoned. Thousands of women-cooks, maids, shopgirls, and housewives-answered their nation's call. These "munitionettes" worked grueling shifts often seven days a week, handling TNT and other explosives...