This chapter deals with civilian private security in relation to public police. It first elaborates, in Section 13.2, on the specific legal norms that govern public and private security personnel and shows that the rise of private security is not the outcome of privatization in the usual sense of the term. It proceeds, in Section 13.3, to present some facts on private security, a large and fast-growing industry in many countries. Sections 13.4 and 13.5 deal with the sources of the demand for private security and its impact on security. We show that this impact is conceptually different from that of public police in a constitutional rule of law state. Private security aims at achieving efficient levels of losses from crime. Public police aim at an equal protection of citizens against crimes. The different objectives have different consequences for security and for the wealth distribution of citizens.