A literature review of 'science' definitions indicates it involves classification, guidelines, rules, generalizations, and laws resulting from inductive or deductive methods; systematically related concepts, propositions, and theories; concern with real-life problems based on curiosity and observation; and temporary conclusions. Criminal justice meets these criteria, but establishing it as a science requires the identification and analysis of scientific aspects of the system. This book does this by delineating important theories related to major criminal justice components: police, courts, and corrections. Police theories address such topics as the police role, corruption, the use of force, police training, discretion, and the police personality. Court theories focus on such issues as arraignment and the preliminary hearing, bail, juries, prosecution, legal representation, and sentencing. Corrections theories cover punishment functions, inequality in administering punishment, and punishment reforms. The book concludes that criminal justice is a science because it is based in certain assumptions and theorems. The assumptions are that persons conform to some of the basic values of their society and that offenders have free will to change their lives. Six criminal justice theorems, which can be proven intuitively, are presented. Chapter notes, 430-item bibliography, and name index.