Before the Central Intelligence Agency, there was the Office of Strategic Services — a clandestine espionage organization of almost 13,000 Americans who, from 1942 to 1945, gathered intelligence for President Roosevelt and wreaked havoc against the Axis powers in every World War II theater. While an ideal O.S.S. recruit was famously described as “a Ph.D. who can win a bar fight,” the staff were diverse in their backgrounds. They came in as academics, military personnel, scientists, athletes, filmmakers, farmers and even some convicts; they served as spies, cartographers, forgers and propagandists. They broke code, planted false information to mislead the Germans and parachuted into enemy territory to blow up bridges and rail lines. One third of them were women.

Their ranks included Marlene Dietrich, the actress, and Margaret Mead, a pioneering anthropologist. Julia McWilliams, later known by her married name, Julia Child, cooked up shark repellent. Jane Wallis Burrell went on to become one of the first C.I.A. operatives killed in the line of duty. Thousands of others broke barriers and demolished stereotypes without ever seeking recognition.

Marion A. Frieswyk, now 97, was the C.I.A.’s first female intelligence cartographer and is the last surviving member of the original O.S.S. mapping division. Virginia Stuart, also 97, worked for the O.S.S. Secret Intelligence branch in Washington, Italy, Egypt and China. These are their stories from 75 years ago, being shared publicly for the first time.