Without being exhaustive, the author studies the major philosophers from the point of view at once expository and critical. It starts by explaining the dissolution of Hegelianism basis in particular Marx and Kierkegaard. The philosophy of life, Schopenhauer and Nietzsche, is presented as a reflection on the meaning of human existence. In positivism, the author sees the incarnation of the spirit of S. XIX. After the French idealism and spiritualism, the book ends with the exposition of Husserl's phenomenology and existentialism.