Andreas Bjerre, author of the volume, The Psychology of Murder, has worked out a method of study of criminal types based upon his prolonged, intimate, and first hand investigations of individual criminals. In this volume, in which he reports upon his observations and interpretations of three typical cases, he makes some very interesting comments upon his methods. This paper is an abstract of the introduction to a paper entitled The Psychology of Murder. The chief interest in this volume to students of criminology and human nature generally is undoubtedly the unique methods employed for the analysis, description, and classification of personality types. These methods are different from but not wholly unlike those employed by Thomas and Znaniecki in their studies of the Polish Peasant.