Herbert Marcuse was a German-American philosopher, sociologist, and political theorist, associated with the Frankfurt School of Critical Theory. Born in Berlin, Marcuse studied at the universities of Berlin and then at Freiburg, where he received his PhD. He was a prominent figure in the Frankfurt-based Institute for Social Research – what later became known as the Frankfurt School. He was married to Sophie Wertheim (1924–1951), Inge Neumann (1955–1973), and Erica Sherover (1976–1979). In his written works, he criticized capitalism, modern technology, historical materialism and entertainment culture, arguing that they represent new forms of social control.