The chapter first examines the general framework of law as it applies to the police management of juveniles, followed by an analysis of the police process for enforcing the law among juveniles. The patrol officer's role is distinguished from that of the juvenile officer, who works in the station house. The chapter next considers police discretion from the perspective of the legal rules that guide the patrol and juvenile officers in making arrests and deciding to file a petition against suspected delinquents. The social context for the operation of legal rules is examined, with attention to the history of policing in the United States. This section concludes that although police work closely with juveniles in their communities, they are an enforcement-oriented group not easily suited to the welfare traditions of juvenile law. The chapter's final two sections consider some scholarly theories about how and why police make their decisions. Although acknowledging the influence of other social elements, such as personal, organizational, and situational factors, the authors reason that all of these factors are informed by a law orientation that makes decisions explainable by reference to the legal rules governing police work. The criteria police invoke to select juveniles for delinquency processing are not easily integrated with due-process principles.