Private law involves the various relationships that people have with one another and the rules that determine their legal rights and duties among themselves. The area is concerned with rules and principles pertaining to private ownership and use of property, contracts between individuals, family relationships, and redress by way of compensation for harm inflicted on one person by another. Historically, government involvement was usually minimal. Private law has also operated to provide general guidelines and security in private arrangements and interactions in ways that are complementary to morality and custom but that are not necessarily enforceable in a court of law, such as noncontractual promises and agreements within an association of private individuals.
The relative significance of purely private law has decreased in modern times. Public law dominates in government-controlled societies; democratic societies increasingly have a mix of public and private law. The private sphere includes individuals and a vast array of groups, associations, organizations, and special legal entities such as corporations and limited companies. They compete with one another and with government for control of resources, wealth, power, and the communication of ideas and values. Special fields of law, such as labour law, facilitate and control this competition. Much of such law is in the commercial and corporate areas. The formerly purely private law of property and contracts, for example, is now overlaid with legislation, regulations, and judicial decisions reflecting the competition. The public law of taxation has significant impact on the whole private sphere. Courts have increasingly regarded resolution of seemingly private disputes as vehicles for response to changing social conditions and values—especially in the United States. Thus, manufacturers have experienced an expansion of liability for physical injuries caused by defects in their products. The mechanism of insurance allows manufacturers to spread such costs across the general consuming public.