Is it possible to get inside the head of one of the greatest thinkers of the twentieth century? John Gerassi gives us this opportunity; Their parents were close friends of Jean-Paul Sartre and Simone de Beauvoir and this enabled him to establish a relationship of absolute trust with your partner. Authorized by Sartre to write his biography, Gerassi conducted a long series of interviews between 1970 and 1974, edited in order to produce this revealing and impressive portrait. In developing these conversations in a relaxed atmosphere, not free of friction, the greater complexities arise Sartre. In particular, we assist in fighting philosopher with the apparent contradiction between his views on freedom and the influence of social conditions in our discussions. It also delves into his considerations on the Spanish Civil War, the Second World War and the disintegration of colonialism, among other topics. Sartre even admits with a laugh that she tried to seduce Gerassi's own mother, without success; great grace also reveals that due to the consumption of amphetamines, had hallucinations with a group of crabs that followed him everywhere. After visiting a psychologist, "a young guy who has since become my friend, Jacques Lacan," concluded that the crabs represented his "fear of losing the peer group." Gathered with remarkable rigor and intensity, these conversations are a fascinating document on one of the most charismatic and controversial representatives of the committed intellectual, who managed to get through with their ideas the minds of many people eager to change society, while still to confront its contradictions, inconsistencies and vagaries.