World War II, the largest and most destructive conflict fought in human history, was the culmination of a process that saw the United States emerge as a global power. The United States had begun playing a larger role in world affairs during World War I, but after the war ended, Americans retreated into isolationism during the 1920s and 1930s, determined to avoid foreign entanglements. In the 1940s, however, the second worldwide conflict of the century ended forever the idea that Americans could withdraw from world events and decisively transformed the United States into a superpower with interests and involvements in every corner of the globe. The war also wrought profound social changes in the United States, and Americans knew even in the midst of the conflict that their world was changing forever.

Because World War II was such a monumental event, spanning most of the globe, there are many stories about people and events to be learned. Ken Burns' documentary The War focuses on four American cities and towns and the fascinating experiences of people from those places during the war. To place those stories in a larger context and give them greater significance, it helps to know the larger global story of World War II. To learn more, explore ABC-CLIO's comprehensive five-volume Encyclopedia of World War II: A Political, Social, and Military History by Dr. Spencer C. Tucker and Dr. Priscilla Mary Roberts. In it you will find an overview, detailed chronology, essays explaining the origins and legacy of the war, and an A-Z entry list. Furthermore, an extensive amount of primary sources—images and documents—provide invaluable insight into the people, places, and events of World War II.