This is a summary report of a two-year study of police unions and their effect on policing and law enforcement. The growth of police unionism in the united states during the 1960's has been a phenomenon of major importance in police management. Police unions in twenty-two urban areas were the target of this field study, during which interviews were conducted with police chiefs or their representatives, city labor relations representatives, police union leaders, and black officer organization leaders. The study explains the influences resulting in the recent rise of militancy in police unions and describes the present nature of these organizations. The effect of the lack of a single employer-figure on the form and conduct of collecting bargaining is discussed, as well as the impact of unions on labor-management relations. The study examines the dimensions of police union bargaining power and the use labor leaders make of this power in varying situations. The relationship between unionization and professionalization is analyzed, as is the impact of police labor organizing on the chief's ability to manage and on the formulation of law enforcement policy. The nature of black officer organizations, and the factors which led to their formation, are compared with similar characteristics of police unions, and the divergence of purpose is examined in relation to intra-departmental racial unrest. Appended is a bibliography on police unions and labor organizations.