存在と無
Being and Nothingness: An Essay on Phenomenological Ontology (), sometimes published with the subtitle A Phenomenological Essay on Ontology, is a 1943 book by the philosopher Jean-Paul Sartre. In the book, Sartre develops a philosophical account in support of his existentialism, dealing with topics such as consciousness, perception, social philosophy, self-deception, the existence of "nothingness", psychoanalysis, and the question of free will.