From 1941 to 1947, the United States planted a liaison mission in the headquarters of Chinese Communist forces behind the lines. Nicknamed the "Dixie Mission," for its location in "rebel" territory, it was an interagency delegation that included intelligence officers from the Office of Strategic Services (OSS).

Mission to Mao is a social history of the OSS officers in the field that reveals the weakness of United States intelligence diplomacy in the 1940s. Drawing on over 14,000 unpublished records from five archives as well as white papers and memoirs from the participants, Sara B. Castro demonstrates how the OSS officers clashed with political appointees and Washington over the direction of the United States relationship with the Chinese Communists. Initially, the OSS officers were sent to gather intelligence that would help the war effort against Japan, but interagency and political conflicts erupted over whether the mission would later involve operations with the Communists. Castro shows how potential benefits for the war effort were thwarted by politicization and the OSS officers' own biases and blind spots.

Mission to Mao is a fresh look at United States intelligence in World War II China and takes listeners beyond the history of "China hands" versus American anticommunists, introducing more nuance.