Europe, 1940. In a stunning blitzkrieg, German troops invaded Denmark and Norway in April, the Netherlands, Belgium, and France in May. The British force in France, cut off from its French allies, was evacuated from Dunkirk, leaving most of its equipment behind.
As Hitler's Panzers drove toward Paris, Winston Churchill, the new British prime minister, made a desperate plea. He secretly asked President Franklin D. Roosevelt to declare an emergency and lend warships, aircraft, and other arms to...