The CIA was created in 1947 to replace the WWII OSS, as it was
now the Cold War, and correct intelligence information was
essential in maintaining the security of the US
Curiously, it was signed into effect by Harry Truman within four
weeks immediately after the Roswell Incident.
Its first director was Roscoe H. Hillenkoetter (former rear
admiral), and the first Secretary of Defense, also created in 1947,
was former Sec. of the Navy, James Forrestal.