What is Philosophy? (French: Qu'est-ce que la philosophie?) is a 1991 book by the philosopher Gilles Deleuze and the psychoanalyst Félix Guattari. The two had met shortly after May 1968 when they were in their forties and collaborated most notably on Capitalism & Schizophrenia (Volume 1: Anti-Oedipus (1972); Volume 2: A Thousand Plateaus 1980) and Kafka: Towards a Minority Literature (1975). In this, the last book they co-signed, philosophy, science, and art are treated as three modes of thought. Source: Wikipedia (en)