The Central Intelligence Agency was created by President Harry Truman
signing into law the 1947 National Security Act, out of the remnants
of the World War II Office of Strategic Services. It was originally
meant to serve as a permanent intelligence gathering body to inform
the President's foreign policy. Thanks to ambiguous language in the
1947 Act, the CIA also derived the power to carry out covert actions,
actions whose authorship could be plausibly denied (as such covert
actions could be secret -unseen by the public - or very public, but
the key was that the hand of the United States would be kept hidden).
The Director of the CIA, currently George Tenet, also oversees the
entire US intelligence community, however inter-agency rivalry usually
means that the different agencies set the priorities of their own
intelligence components. The CIA is one of many intelligence bodies
of the US government.