This volume, which was originally presented to the Sorbonne as a dissertation (1874), revived in 1895 and now translated, is a brilliant presentation of some ideas now long current. M. Boutroux treats the problem of contingency with that delightful dialectic of which the French are masters. The fundamental thesis of the book is that phenomena are not subject to the laws of nature. The laws "express only the relations that are due to their previously realized nature" (p. 155). The contingency of the laws of nature is indicated, among other things, by the mutability of species and the impossibility of accounting for living and conscious beings by the operation of physical and physiological laws. The positive result which M. Boutroux reaches is the fact of human freedom. He considers that the Beings of nature have a further task than merely to continue in existence. They must realize an ideal. In order to realize this ideal, which is highly developed in man, we find him endowed with free will, which is the power to choose between good and evil. The appearance of necessity in the world is caused by the fact that the ideal of the world is attempting to realize itself. The ultimate support of this entire scheme of nature and freedom is God, who not only creates beings but is the ideal which guides their development. As long as M. Boutroux criticizes the assumption of an ultimate mechanical explanation of phenomena he is contributing to our understanding of experience. When he substitutes rather arbitrarily another ultimate he makes his argument lose most of its point. In general the tone of the book is that which characterized much of the reaction to Darwinism in its early career. A possible reason for the revival of the volume now is to be found in the stimulating challenge of current events for final explanations of human conditions. -International Journal of Ethics, Vol. 28