This chapter focuses on the criminal justice system. It contains summaries of the different social theories that underpin both the criminal justice system and the fundamental principles relating to sentencing policy. The system is examined in three segments: pre-trial stages, trial stage, and post-trial stages. Each is discussed in turn. This chapter emphasizes the holistic approach by looking not only at what happens in courts, but also the police station and in post-trial contexts such as parole and criminal cases review. The place of the victim in the system is also considered. Attention is given to the need to improve the criminal justice system.