Founding Under the National Security Act

The Central Intelligence Agency traces its authority to the National Security Act of 1947, which President Harry Truman signed on 26 July 1947 to reorganize the United States' military and intelligence establishment for the emerging Cold War. The Act formally replaced the Central Intelligence Group, a temporary body created in January 1946 out of the disbanded wartime Office of Strategic Services, with a permanent, statutorily independent civilian agency charged with coordinating the government's intelligence activities and briefing senior officials, and most of its provisions took effect on 18 September 1947.

Unlike the military intelligence services it was meant to coordinate, the CIA was designed to sit outside the Department of Defense, reporting through the National Security Council directly to the President, a structure meant to prevent any single service branch from controlling the nation's central intelligence estimates. Over its subsequent history the Agency built an extensive apparatus for espionage, covert action and analysis, and during the Cold War its research arms periodically explored unconventional and speculative methods of intelligence collection alongside conventional human and technical programs, a pattern that eventually included funding contract research into claimed psychic abilities.