The detonation of the first atomic bomb in July 1945 started the Atomic Age, an era in which the fear of nuclear attack and the promise of nuclear power pervaded American culture. Less than a month later, two atomic bombs were dropped on Japan, killing at least 129,000 Japanese, and precipitating the end of World War II in the Pacific. The bombs caused some to see the possibilities for harnessing the power of atomic energy for good, while many feared the further development of atomic energy for war. The Cold War of the 1950s and 1960s between the US and the Soviet Union was largely forged by this fear of nuclear war. Each nation raced to develop more and more powerful bombs pointed at one another’s shores. The resources here, including letters, photographs, official documents, and film, represent various aspects and visions of the Atomic Age.