Law is a system of rules that a particular nation or community recognizes as regulating the behavior of its citizens. Oxford Reference provides clear definitions and expert, encyclopedic coverage of all aspects of this broad subject, from legal theory to the practical application of laws in different societies.
There are many fields of law, but the core subjects include contracts, criminal justice and property. Contract law concerns the agreements that people may enter into with each other to exchange goods, services or anything else of value; criminal justice law encompasses all forms of prosecution and punishment for crimes; and property law defines rights and duties toward tangible property, whether it is real estate (land) or personal possessions like cars or clothes.
Because of its normative character, law is unique from empirical sciences such as physics (as with the law of gravity) or social science such as economics (as with the law of supply and demand). It is impossible to prove, by means of any empirical process, what the contents of any given law should be, but this does not preclude its existence, for the mere fact that something is a law does not make it right.
A major function of law is to maintain peace and preserve the status quo, although it may also serve as a tool for minorities to protect themselves against majorities, or to bring about social change in an orderly fashion. These functions are served more successfully by stable or democratic governments, while authoritarian and undemocratic nations tend to fail to fulfil these roles.