Discretion begins with the decision to label certain acts as criminal and is followed by a series of subsequent decisions made by police officers, judges, prosecutors, and others. As a result, the objective ideal gives way to individual personal judgment, both in a collective sense and in an organizational sense. This occurs because the organizational structure of the criminal justice system is bureaucratic. Such structures are governed by formal rules which tend to be informally implemented. How rules, regulations, and the law are implemented is determined by the role perception of the implementers, their ideological orientation, and demographic characteristics. Greater understanding of the role of discretion, its achievements, and shortcomings will permit better regulation of it. Its major drawback is that such decisions are essentially unreviewable and have a significant potential for being arbitrary and capricious. In addition, many decisions are heavily influenced by the internal values, goals, and purposes of the various units within the system. Both politicians and the public, through their interactions with one another and with the criminal justice system, influence its operation. These complex interactions are to be expected in a democratic society, where laws provide a basis for action but do not define it. Detailed analyses of discretion in each component of the system and chapter notes are supplied.