FOR FIRST-LINE POLICE SUPERVISORS AND THOSE WHO ASPIRE TO BECOME SERGEANTS, THE MATERIAL PRESENTED IS BASED ON AN EXTENSIVE STUDY OF THREE MAJOR MIDWESTERN POLICE DEPARTMENTS. INTERVIEWS WERE CONDUCTED WITH 300 POLICE OFFICERS OF ALL RANKS WHOSE ACTIONS WERE OBSERVED, FOCUSING ON THE ROLE OF THE SERGEANT AS PERCEIVED BY THE SERGEANTS THEMSELVES, THE OFFICERS THEY SUPERVISED, AND THE PEOPLE WHO SUPERVISED THE SERGEANTS. ORGANIZATIONAL AND SUPERVISORY STYLES ARE EXAMINED WITH ATTENTION TO MANAGEMENT STYLES AND ORGANIZATIONAL CONTROL. STUDYING THE SERGEANT AS THE MAN IN THE MIDDLE REVEALS THE ADVANTAGES AND DISADVANTAGES OF BEING A SERGEANT, THE SERGEANT'S ROLE AS A MOTIVATOR AND MORALE BUILDER, AND THE SERGEANT'S RESPONSIBILITY FOR DISCIPLINE AND ACCOUNTABILITY. AN OVERVIEW OF THE SERGEANT AS A LEADER DELVES INTO THEORIES AND TYPES OF EFFECTIVE AND INEFFECTIVE LEADERSHIP. DETAILS ON THE SERGEANT'S OPERATIONAL ROLE COVER COMMUNICATION, INSPECTION, DIRECTION, DISCIPLINE, INVESTIGATION, GRIEVANCE HANDLING, AND TIME ALLOCATION. PROMOTIONAL PRACTICES FOR POLICE SUPERVISORS ARE DISCUSSED; MODELS FOR EVALUATION AND CAREER DEVELOPMENT ARE PROVIDED. THE ROLE OF THE SERGEANT IS ALSO VIEWED WITHIN THE CONTEXT OF THE HISTORY OF THE POLICE SYSTEM IN ENGLAND AND WALES, OF A DEVELOPING POLICE SYSTEM, AND OF THE ORIGINS OF THE RANK SYSTEM. THE SERGEANT'S MANAGEMENT OF STRESS IS DESCRIBED, ALONG WITH THE SERGEANT'S RESPONSIVENESS TO DEPARTMENT AND COMMUNITY NEEDS. SHORT SUMMARIES OF EACH TOPIC AREA ARE PROVIDED, ALONG WITH AN INDEX, A BIBLIOGRAPHY, AND AN APPENDIX CONTAINING THE INTERVIEW QUESTIONNAIRE. (MHP)