The effects of criminal activity, as well as people's perceptions about the extent of such activity, are issues which impact directly or indirectly on the quality of people's lives. This chapter provides an overview of the Australian criminal justice system. Many of the data presented are based on national crime and justice statistics produced by the Australian Bureau of Statistics. These are sourced from surveys such as the Crime and Safety Survey and administrative by-product collections, covering crimes recorded by police, caseflow information for criminal courts, and information on prisoners dealt with by correctional services agencies. The objective of national crime and justice statistics is to standardise data in order to make them comparable across the different systems of criminal law in Australia, and so provide indicators of the level and nature of crime and the activities of criminal justice agencies. The chapter also draws upon data sources other than the Australian Bureau of Statistics to ensure a more complete coverage of issues relevant to crime and justice.