The author shows in her writing that – contrary to many bourgeois interpretations – the Marxism of Sartre is not a negligible "disability" in his existentialism but integrant part of his thinking. The Marxism of Sartre becomes exactly fundamental in the humanism of his existentialism as the conscious and deliberate choice for responsibility of a human and intellectual. Thus the Marxists writings and thoughts of Sartre are not detours but in practice logical results of his oeuvre.