On 6 June 1944, in what would become known as D-Day, Allied forces launched a naval, air and land assault on Nazi-occupied-Normandy, France. The attack, codenamed Operation Overlord, took place in the aftermath of Nazi Germany’s invasion of France in May 1940 and Japan’s attack on Pearl Harbor in 1941, which forced the United States to enter World War II. In the months leading to the invasion, the Allied forces created a phantom army commanded by George Patton, using tactics such as double agents and fraudulent radio transmissions to deceive the Germans into thinking that the main invasion targeted was...