Every theory of private law has to deal with the fact the law is just one means among many that private parties can use to order their relationships. This fact concerns every area of life, from families to corporations. Even if there are no formal laws regulating a certain area, there are nevertheless norms that determine how people behave, how others will judge their behaviour, and how deviant behaviour is sanctioned. In some instances, these norms can be considered as a form of private ordering. Here, private actors establish a normative order with effects comparable to those of state law (public ordering). The norms of private ordering that this chapter deals with are especially widespread where ‘official’, state-made law has little or no effect.