Between 1943 and 1950, Marcuse worked in U.S. Government service for the Office of Strategic Services (predecessor of the Central Intelligence Agency) and criticized the ideology of the Communist Party of the Soviet Union in the book Soviet Marxism: A Critical Analysis (1958). After his studies, in the 1960s and the 1970s he became known as the pre-eminent theorist of the New Left and the student movements of West Germany, France and the United States.