It is not easy for an Englishman to acquire a competent knowledge of French philosophy. For one thing there are so many French philosophers writing so many books, and for another the multiplicity of men is matched by the variety of views. In a country where a knowledge of philosophy is expected of any cultivated man, and where the flourishing of philosophy in school and university curricula is regarded as a condition of intellectual freedom, this variety is accepted as part of the cultural background. Professor Bréhier's Transformation de la Philosophie Française (Flammarion, Paris, 1950) must, even so, be of great value to French readers, because of the author's capacity-so admirably shown already in a History of Philosophy that is unquestionably the best now obtainable-to pick out what is essential in a welter of theories, arguments, and mere pronouncements. To English readers, whose knowledge of the background is necessarily limited, this book is particularly valuable, not only for the clarification it brings, but also for a bibliography that is closely related to the text. M. Bréhier observes that French philosophers of the generation that followed and criticized Durkheim, Bergson and Brunschwicg showed themselves acutely conscious of the discontinuities of things, and puritanically averse to the construction of philosophical systems. (We may compare the roughly contemporaneous reaction in this country against the systems of Bosanquet and Alexander, though the arguments were for the most part very different.) M. Bréhier, however, does not take this anti-systematic, pluralist tendency at its own valuation. French philosophy, he thinks, is in a phase that makes it comparable to medieval philosophy. It was characteristic of medieval philosophy that it comprised no individually constructed systems like those, for example, of Descartes, Leibniz, Hegel, and Schopenhauer, which have grown up and died away in Europe since the Renaissance. The main reason for this was that Christianity itself provided a common system which was never to be questioned, so that philosophers concerned themselves not with systems, for that would have led to heresy, but with particular problems. Part of M. Bréhier's parallel with modern times is that some Christians and all Marxists aim to produce the same condition.