The document discusses the nuclear arms race between the United States and Soviet Union from the late 1940s through the 1980s. It describes how both nations engaged in an escalating arms buildup, developing new weapons like ICBMs, SLBMs, and MIRVs. It also discusses key events and agreements that shaped the arms race, such as the Soviet testing of nuclear weapons in 1949, the Cuban Missile Crisis in 1962, and arms limitation treaties like SALT I and SALT II. Throughout this period, both superpowers pursued policies of deterrence based on the threat of mutually assured destruction.