The authors recognize that the so-called pluralization of policing is gathering momentum and that new models are required to take into account the blurring of what have conventionally been considered parallel systems, with private security as very much the lesser or junior entity. They introduce several Australian examples into the debate and develop a set of descriptive models to account for and explain the main types of existing and emerging relationships. The authors then present a prescriptive model to support the view that caution should temper any push toward totally symbiotic cooperation between public and private policing. They conclude the best relationship for the future may be one that maintains a basic separation of powers, with some operational cooperation only where essential and where oversight can be provided by executive-level standing committees. 84 references and 2 footnotes