THE RESEARCH STRATEGY INVOLVED COMPARING A HIGH-CRIME DIVISION OF A LARGE, URBAN POLICE DEPARTMENT (LOS ANGELES POLICE DEPARTMENT) WITH A HIGH CRIME SMALL DEPARTMENT (INGLEWOOD, CA); AND A LOW-CRIME DIVISION OF THE LARGE DEPARTMENT WITH A LOW-CRIME SMALL DEPARTMENT (REDONDO BEACH, CA). DATA FOR THE STUDY WAS COLLECTED BY PARTICIPANT OBSERVATION AND A SURVEY OF 200 PATROLMEN AND 65 MANAGEMENT PERSONNEL IN THE THREE DEPARTMENTS. THE ORIENTING HYPOTHESIS WAS THAT THE EXERCISE OF DISCRETION BY PATROLMEN IS SHARED BY THE INCENTIVES AND PRESSURES OF THE POLICE BUREAUCRACY AND THE VALUES OF THE POLICE CULTURE. THE STUDY FOUND SIGNIFICANT DIFFERENCES IN THE WAY PATROLMEN EXERCISE THEIR DISCRETION BETWEEN THE THREE DEPARTMENTS AND BETWEEN INDIVIDUAL PATROLMEN WITHIN THE DEPARTMENTS. PATROLMEN IN THE LARGE DEPARTMENT WERE MORE LIKELY TO ENFORCE THE LAW OR TAKE OTHER FORMAL ACTIONS IN A WIDE VARIETY OF SITUATIONS THAN PATROLMEN IN THE SMALL DEPARTMENTS. IN ADDITION, PATROLMEN WERE FOUND TO HAVE CONSIDERABLE AUTONOMY IN DECIDING HOW TO GO ABOUT USING THEIR POWERS OF DISCRETION, TO BE MOTIVATED BY THE IDEAL OF THE INNER DIRECTED, AGGRESSIVE POLICEMAN, AND TO DEFINE THEIR TASK IN TERMS OF THE GOAL OF CRIME-FIGHTING. A TYPOLOGY OF FOUR DISTINCTIVE OPERATIONAL STYLES, BASED ON THE DIMENSIONS OF AGGRESSIVENESS AND SELECTIVITY, WERE IDENTIFIED - THE OLD-STYLE CRIME-FIGHTER; THE CLEAN BEAT CRIME-FIGHTER; AND THE PROFESSIONAL; AND THE SERVICE STYLES. THE ANALYSIS SHOWED THAT THESE STYLES DETERMINE HOW AN OFFICER WILL USE HIS DISCRETION IN SOME SITUATIONS AND THAT THEY DEVELOP INDEPENDENT OF THE POLICE DEPARTMENT--THAT IS, POLICE DEPARTMENTS DO NOT PRODUCE DISTINCTIVE STYLES OF POLICE WORK. POLICE PROFESSIONALISM AND THREE MODELS OF REFORM, ALL GEARED TO GAINING GREATER POLITICAL CONTROL OVER POLICE DISCRETION - THE POLICY-MAKING, PROFESSIONAL, AND COMMUNITY CONTROL/ DECENTRALIZATION MODELS - ARE EVALUATED IN LIGHT OF THESE CONCLUSIONS. A 29-PAGE BIBLIOGRAPHY IS INCLUDED. APPENDED ARE A DISCUSSION OF STUDY AND DATA ANALYSIS METHODS AND A COPY OF THE SURVEY INSTRUMENT. (AUTHOR ABSTRACT MODIFIED)