In this work Le Bon makes a careful study of the character and scope of the activities of crowds and mobs. He bases all his propositions about these phenomena on his general theory of the nature of social interpretation as set forth in his prior work, Lois psychologiques de l’évolution des peuples. This theory involves a very sharp distinction between the social institutions and the social soul, the institutions being simply manifestations of the soul, and the latter alone a living or creative element. L’âme du peuple must then be studied first and foremost by the sociologist and all social phenomena must be explained by reference to this soul as cause. (...) The translation is as a whole very satisfactory, though occasionally an amusing error creeps in; rarely, however, to the serious detriment of the sense. Despite the general good appearance of the volume, the student cannot but regret the tripling in both bulk and price which it has undergone in the process of reproduction. — Arthur F. Bentley, American Journal of Sociology, Vol. 2, No. 4.