Slavoj Zizek is a senior researcher at the Institute of Sociology, University of Ljubljana, Slovenia, and has been a visiting professor at Columbia University, Princeton, and The New School. Arguably the only living philosopher who uses positively the terms "dialectical materialism" and "dictatorship of the proletariat," his work is controversial and has gained him a large following internationally. A philosopher and psychoanalyst, he is the author of more than thirty books and is the subject of the documentary Zizek!. His own critically acclaimed documentary, The Pervert's Guide to Cinema, was the subject of a film retrospective in 2007 at the Museum of Modern Art.