Both the Allies and the Nazis were always looking for a single knock-out blow to end the war. Britain’s Sir Arthur “Bomber” Harris thought the answer might lie in “strategic bombing.” This, he argued, would cripple the Nazis’ ability to wage a war and the ordinary people would soon lose the will to fight. But it led directly to the tragedy of Dresden, when Allied planes firebombed tens of thousands of ordinary Germans. The Germans believed that the knock-out blow would come from their submarines. If they could only cut American supply lines to Britain across the Atlantic, then the Allied effort would collapse. So began a long game of cat-and-mouse between U-Boats and British and American convoys.