The OSS or Office of Strategic Services was the forerunner to the modern day Central Intelligence Agency.
Office of Strategic Services was established by a Presidential military order issued by President Roosevelt on June 13, 1942, to collect and analyze strategic information required by the Joint Chiefs of Staff and to conduct special operations not assigned to other agencies.
One of the greatest accomplishments of the OSS during World War II was its penetration of Nazi Germany by OSS operatives. The OSS was responsible for training German and Austrian individuals for missions inside Germany.
At the height of its influence during World War II, the OSS employed almost 24,000 people.
The names of all OSS personnel and documents of their OSS service, previously a closely guarded secret, were released by the US National Archives on August 14, 2008