ALL THEORIES OF CRIMINOLOGY SHOULD PROCEED FROM THE ASSUMPTION THAT CRIME IS BEHAVIOR. THIS ASSUMPTION HAS TWO IMPORTANT CONSEQUENCES: (1) THERE IS A NEED FOR A DIFFERENTIAL CRIMINOLOGY (ONE THAT TAKES INTO ACCOUNT THE DIVERSE BEHAVIORS CONSIDERED CRIMINAL) AND (2) TO EXPLAIN CRIMINALITY, CRIMINOLOGISTS MUST ADOPT A BEHAVIORAL APPROACH. MOST CRIMINOLOGICAL THEORIES CLAIM TO EXPLAIN ALL CRIMINALITY, NEGLECTING THE FACT THAT CRIME IS A HETERGENEOUS PHENOMENON. TO BETTER UNDERSTAND CRIMINAL BEHAVIOR, IT IS ESSENTIAL TO STUDY MORE HOMOGENEOUS GROUPS. A MODEL CLASSIFYING OFFENDERS INTO HOMOGENEOUS GROUPS ACCORDING TO TYPE OF OFFENSE, AGE, SEX, SOCIAL CLASS, AND WHETHER THE OFFENSE WAS COMMITTED ALONE OR WITH OTHERS IS PRESENTED. SUCH A MODEL FACILITATES A DIFFERENTIAL APPROACH TO THE STUDY OF CRIMINAL BEHAVIOR. BY COMPARING SUBCATEGORIES OF OFFENDERS WITH EACH OTHER AND WITH NONCRIMINAL CONTROLS, THE CHARACTERISTICS OF A PARTICULAR GROUP OF OFFENDERS CAN BE UNDERSTOOD. THE POINT OF DEPARTURE FOR A BEHAVIORAL APPROACH TO EXPLAINING CRIMINALITY IS THE VIEW THAT ALL BEHAVIOR IS A FUNCTION OF THE PERSONAL CHARACTERISTICS OF THE INDIVIDUAL AND THE CHARACTERISTICS OF THE INDIVIDUAL'S SITUATION. A FORMULA EXPRESSING CRIMINAL BEHAVIOR IN TERMS OF THESE CHARACTERISTICS IS PRESENTED. THE FORMULA ENCOMPASSES THREE SITUATIONAL LEVELS (MICRO, MESO, AND MACRO) AND A NUMBER OF PERSONAL CHARACTERISTICS (GENETIC, ENDOCRINOLOGICAL, NEUROPHYSIOLOGICAL, BIOCHEMICAL, PSYCHOPHYSIOLOGICAL, ORGANIC, PSYCHIATRIC, PSYCHOLOGICAL, SOCIOLOGICAL, ATTITUDINAL, ETC.). TO USE THE FORMULA IN THE STUDY OF CRIME, AN INTERDISCIPLINARY APPROACH IS REQUIRED. A MODEL TO GUIDE THE DEVELOPMENT OF AN INTERDISCIPLINARY APPROACH IS PRESENTED. WITHIN THE MODEL ALL RELEVANT DISCIPLINES APPLY THE PRINCIPLES OF DIFFERENTIAL CRIMINOLOGY TO DRAW COMPARISONS OF CRIMINALS AND NONCRIMINALS RELATIVE TO THE CHARACTERISTICS EMBODIED IN THE BEHAVIOR-PERSON-SITUATION FORMULA, THUS PROVIDING INFORMATION ON PREDISPOSING, FACILITATING, AND INHIBITING FACTORS VIS-A-VIS THE PROBABILITY OF CRIMINAL BEHAVIOR. STEPS TO IMPLEMENT THE MODEL ARE OUTLINED. (1KM)