World War IIWorld War II was the largest conflict in human history and devastated Europe, Asia, North Africa, and large portions of the Pacific. It began as two separate wars: one involving Japan against China in the 1930s; the other involving Germany against Poland, France, and Great Britain in 1939. With the entry of the United States into both wars in December 1941, the two conflicts merged into a single global struggle during which a coalition of Allied powers (the United States, the Soviet Union, Great Britain, China, Free France, and a host of smaller nations) defeated a coalition of Axis states (Germany, Italy, Japan, and smaller satellites). This article uses a largely narrative approach, interspersed with a separate section on economic, psychological, and demographic aspects of the conflict, to describe the origins, course, and consequences of the war.