Louis Francis Budenz (pronounced "byew-DENZ"; July 17, 1891 – April 27, 1972) was an American activist and writer, as well as a Soviet espionage agent and head of the Buben group of spies. He began as a labor activist and became a member of the Communist Party USA. In 1945, Budenz renounced Communism and became a vocal anti-Communist, appearing as an expert witness at governmental hearings and writing about his experiences.