What was the immediate forerunner of the US Central Intelligence Agency?

Although the Central Intelligence Agency (CIA) has its roots in the formation of the Office of Strategic Services (OSS), its immediate parent agency was the Central Intelligence Group of the National Intelligence Authority.

Prior to June 13, 1942, the United States had no one agency that operated on foreign soil. Each branch of the military had its own intelligence-gathering units. However, US President Franklin Delano Roosevelt was so impressed by the British Secret Intelligence Service (MI6), Special Operations Executive, and commandos that he pressed for the formation of the OSS, which was created on June 13, 1942 as an agency of the Joint Chiefs of Staff.

When World War II ended, US President Harry S. Truman dissolved the OSS, dividing its responsibilities between the US Departments of War and State on September 20, 1945. The term “Central Intelligence Agency” was first officially used internally by the US federal government some time near the end of 1945. Although the military, State Department, and Federal Bureau of Investigation—which, now as then, operates only domestically—objected, Mr. Truman created the National Intelligence Authority in January, 1946. The operations arm of the NIA was the Central Intelligence Group.

On July 26, 1947, Mr. Truman signed the National Security Act into law. Part of this legislation ended the NIA and the CIG while establishing both the National Security Council and the CIA.