At the beginning of 1943, World War II was considered to be decided - or so the common assessment went. However, there were still enormous challenges to overcome before the final victory of the Allies. The German Reich only reached the peak of its armaments production in 1943, boasting a powerful army of millions and a dangerous submarine fleet. Japanese troops had entrenched themselves on the islands of the Pacific. The notion that the war would end in 1945 was far from certain. Bestselling author Paul Kennedy describes how the Allies gained the upper hand in the months between the Casablanca Conference in January 1943 and the invasion of Normandy in June 1944. However, his focus is not on the statesmen and a top-down history. Instead, he looks over the shoulders of the "doers" and "problem solvers," whose technical innovations played a crucial role.