Although America proclaimed its neutrality when World War II broke out in Europe in 1939, in just a few years it would not only be forced into the bloodiest conflict in world history but would also determine the war’s outcome. The unimaginable horrors of the Holocaust were revealed when U.S. and Allied troops liberated concentration camps. Then, in 1945, the United States gave birth to the nuclear age when it dropped atomic bombs on Japan. In the peace that followed, the cold war and the arms race escalated, the Korean War broke out, and, at home, the civil rights movement took hold, resulting in anti-black violence and hate crimes, race riots, and political assassinations. This bloody and transformative period of American history is told in vivid detail with the help of an abundance of primary source materials.