United States. Office of Strategic Services

Formed on June 13, 1942, the Office of Strategic Services was the United States' wartime intelligence agency during World War II. It was built to collect and analyze information and to carry out special operations behind enemy lines, bringing together research, espionage, sabotage, and support for resistance movements.

The OSS was led by William J. Donovan, often called "Wild Bill" Donovan. Under his leadership, the organization operated across Europe, Asia, and other theaters of war, developing a reputation for inventive training, unconventional tactics, and a mix of military and civilian talent.

Although the OSS was dissolved in 1945, its influence lasted well beyond the war. It is widely seen as an important predecessor to later U.S. intelligence institutions, especially the Central Intelligence Agency.