These three books comprise a part of the special group of publications called the “Longmans’ Social Science Series,” written by eminent professors of sociology, edited by Ernest R. Groves, Professor of Social Science in the University of North Carolina and treating of several aspects of sociology. They represent the accumulation and digested survey of a vast amount of data on the subject of human relationships.

The volume by Professor Duncan begins with a brief but comprehensive account of the theories of the origin of man, his universal dissemination, the formation of races and racial characteristics and the classification of these types. It then proceeds to the discussion of such biological and racial problems as are found in the concepts of heredity and eugenics, the notions of inferiority and superiority, and in the complexities created by the amalgamation of races. A special chapter is