The Central Intelligence Agency, or CIA, is America’s primary intelligence service. Its missions are to gather and analyze intelligence from around the globe, prevent other nations or agencies from gathering sensitive information on the United States, and engage in covert operations overseas in such a way that the United States government can deny involvement. This entry covers the history of the CIA and its operations, from its emergence after World War II to 21st-century conflicts, and examines in detail the criticisms of agency’s methods and successes and failures in gathering intelligence to promote national security.

The forerunner to the CIA was the Office of Strategic Services (OSS) in World War II; the CIA was created shortly after that conflict by the National Security Act of 1947. ...