It is strange that not in any language has there been published a systematic treatise on Ethnic Psychology; strange, because the theme is in nowise a new one but has been the subject of many papers and discussions for a generation; indeed, had a journal dedicated to its service for a score of years; strange, also, because its students claim that it is the key to ethnology, the sure interpreter of history, and the only solid basis for constructive sociology. Why this apparent failure to establish for itself a position in the temple of the Science of Man? This inquiry must be answered on the threshold of a treatise which undertakes to vindicate for this study an independent position and a permanent value.