THE IMPORTANCE OF GENETIC AND PHYSIOLOGICAL FACTORS IN DETERMINING CRIMINAL BEHAVIOR IS BELIEVED ESTABLISHED IN THESE STUDIES; HOWEVER, THE CAUSATIVE STRENGTH AND MANIFESTATION PATTERNS OF THESE BIOLOGICAL FACTORS ARE CONSIDERED DEPENDENT ON SOCIAL VARIABLES. AUTONOMIC NERVOUS SYSTEM VARIABLES ARE DISCUSSED EXTENSIVELY THROUGHOUT THE BOOK. THESE VARIABLES HAVE BEEN SHOWN TO EXPLAIN IMPORTANT AMOUNTS OF VARIANCE IN CRIME. A THEMATIC CONCLUSION EVIDENCED IN THE STUDIES MAINTAINS THAT GENETIC AND PHYSIOLOGICAL FACTORS PLAY A STRONG ROLE IN DETERMINING MIDDLE-CLASS CRIMINAL BEHAVIOR, WHILE BEING RELATIVELY WEAK IN EXPLAINING CRIMINALITY AMONG THE LOWER CLASS. ACCORDING TO THESE STUDIES, IN ORDER TO SEE THE ACTION OF SOCIAL FORCES WITH SOME DEGREE OF PRECISION, THE VARIANCE ATTRIBUTABLE TO GENETIC AND PHYSIOLOGICAL FACTORS MUST FIRST BE IDENTIFIED. THE STUDIES ILLUSTRATE METHODS OF ANALYSIS WHEREBY THIS CAN BE ACCOMPLISHED. REFERENCES ARE LISTED, AND NAME AND SUBJECT INDEXES ARE INCLUDED. (RCB)