In late summer 1939, the French learned that Adolf Hitler had attacked Poland. On September 3, France entered the war, twenty years after the carnage of World War I. Although France was considered the world’s leading military power, with a vast empire and a powerful ally in the United Kingdom, everyone was overcome with a sense of dread. Yet the fighting would not begin until May 1940 and would end with France’s defeat in June. How did the French people experience those few months—among the most decisive and darkest in the country’s history?