SINCE THE 19TH CENTURY A NUMBER OF THEORIES AND STUDIES HAVE ATTEMPTED TO SHOW A RELATIONSHIP BETWEEN CONSTITUTIONAL CHARACTERISTICS AND CRIMINALITY OR DEVIANCE. PHRENOLOGY STUDIED THE CONFORMATIONS OF THE SKULL AND RELATED THEM TO PARTICULAR FACULTIES OF THE MIND. IT ENJOYED A VOGUE IN THE DIAGNOSIS OF CRIMINALS AND SUCH CLASSIFICATION WAS RECOMMENDED IN LIVINGSTON'S INFLUENTIAL PENAL CODE. BASED ON SIMILAR ASSUMPTIONS, LOMBROSO PROPOSED THE THEORY OF CRIMINAL ATAVISM WHICH SUGGESTED THAT CRIMINALITY WAS A FORM OF EVOLUTIONARY REVERSAL AND THAT PRIMITIVE STIGMATA SUCH AS LOW FOREHEADS OR CROOKED NOSES WERE MORE PREVALENT IN CRIMINALS. HOOTEN REAFFIRMED LOMBROSO'S POSITION, AND ON THE BASIS OF A STUDY OF PRISONERS AND NONCRIMINALS HELD THAT CRIME IS CAUSED BY BIOLOGICAL INFERIORITY WHICH IS REFLECTED IN THE ANATOMY. SHELDON AND GLUECK'S THEORIES OF SOMATOMORPHS IN CRIMINALS AND JUVENILE DELINQUENTS RESTATED HOOTEN'S ANALYSIS. MOST OF THE STUDIES SUPPORTING THESE THEORIES HAD SERIOUS SAMPLING AND INTERPRETIVE FLAWS; FURTHERMORE THE BIOLOGICAL CHARACTERISTICS NOTED ARE FOUND IN NONCRIMINAL POPULATIONS AS WELL AND THERE IS NO STANDARD OF NORMALITY TO WHICH CRIMINAL BIOLOGY CAN BE COMPARED. SINCE THE FAMOUS STUDY OF THE JUKES AND KALLIKAKS, A NUMBER OF THEORIES HAVE TRIED TO LINK HEREDITY AND CRIME. GORING, FINDING CORRELATIONS IN FAMILIAL INCIDENCE OF CRIMINALITY, WENT ON TO ASSERT THAT CRIMINALITY MUST BE INHERITED IN A MANNER ANALOGOUS TO PHYSICAL CHARACTERISTICS. MORE RECENT STUDIES HAVE EXAMINED CRIMINALITY IN MONOZYGOTIC TWINS AND IN MALES WITH AN EXTRA Y CHROMOSOME (47,XYY MALES). WHILE SUGGESTING THE POSSIBILITY OF A GENETIC INFLUENCE. STUDY SAMPLES HAVE OFTEN BEEN SMALL, FINDINGS CAN BE EXPLAINED NONGENETICALLY, AND GENERALIZATION OF FINDINGS IS PREMATURE. A MAJOR DIFFICULTY WITH STUDIES THAT HAVE ATTEMPTED TO LINK CRIMINALITY WITH MENTAL DEFICIENCY IS THE QUESTIONABLE VALIDITY AND RELIABILITY OF INTELLIGENCE TESTS AND SCALES. THEORIES POSITING A HORMONAL IMBALANCE OR AN ASSOCIATION BETWEEN CRIMINALITY AND TESTOSTERONE HYPERACTIVITY REMAIN TO BE DEFINITELY PROVEN, AND WELL-DESIGNED EXPERIMENTS HAVE NOT BEEN PERFORMED. STUDIES OF A POSSIBLE CORRELATION BETWEEN NEUROLOGICAL DISORDER AND DEVIANCE WHICH MAY RESULT IN CRIMINAL ACTS HAVE HAD VERY MIXED FINDINGS. MOST OF THE STUDIES HAVE RELIED ON ELECTROENCEPHALOGRAPHIC (EEG) EVALUATIONS WHICH ARE OPEN TO SUBJECTIVE BIAS IN THEIR INTERPRETATION AND YIELD RATHER GENERAL NEUROLOGICAL INFORMATION. MUCH ATTENTION HAS BEEN GIVEN TO THE EPISODIC DYSCONTROL SYNDROME, PARTICULARLY THE WORK OF MARK AND ERVIN. MARK AND ERVIN SUGGEST THAT ABNORMAL VIOLENT AND AGGRESSIVE BEHAVIOR CAN BE ELIMINATED THROUGH STEREOTACTIC REMOVAL OF PATHOLOGICAL BRAIN TISSUE WHICH HAS BEEN LOCATED BY DEPTH ELECTRODE IMPLANTS. ALL OF THE THEORIES AND STUDIES REVIEWED SUFFER FROM SIMILAR EMPIRICAL FAULTS. IN MANY CASES THE PHENOMENON UNDER STUDY IS NOT CLEARLY DEFINED. SAMPLING ERRORS ARE COMMON. RELEVANT CONTROLS ARE LACKING. TECHNIQUES OF INVESTIGATION AND MEASUREMENT LACK SUFFICIENT REFINEMENT. INTERPRETATIONS AND CONCLUSIONS ARE FREQUENTLY NOT JUSTIFIED BY THE DATA. IT IS CONCLUDED THAT IN GENERAL THE BIOMEDICAL APPROACH TO CRIMINALITY LACKS SCIENTIFIC CREDIBILITY. REFERENCES ARE INCLUDED. (JAP)