The Office of Strategic Services (OSS) was a wartime intelligence agency of the United States established by Franklin Roosevelt during World War II, and a predecessor of the modern Central Intelligence Agency (CIA). The OSS was formed as an agency of the Joint Chiefs of Staff (JCS) to collect and analyze strategic intelligence, run special operations, and coordinate espionage activities behind enemy lines.
(From: http://www.history.com/news/oss-the-predecessor-of-the-cia)
Office of Strategic Services 1942-45 by 
Operatives, Spies, and Saboteurs by 
