Law is the set of rules that a society creates and enforces to regulate behavior. It is an area of study that encompasses many disciplines, including philosophy, history, economic analysis and sociology. The precise definition of law has long been a subject of debate, but most scholars agree that it involves an institution’s power to impose restrictions on individuals or organizations, and the mechanisms by which those restrictions are enacted. The concept of law is also linked to the notion of justice, with laws and judicial decisions being seen as ways to ensure fairness and equality in society.

Legal systems vary widely, with some based on religion (e.g. Jewish halakha and Islamic Shari’ah) and others based on human elaboration and interpretation, such as English common law. Some legal systems are derived from codes, such as the Roman law system which was highly codified during the ancient period; other laws are compiled through judicial decisions, which become case law. In “common law” systems such as the United States, judicial decisions are considered law on an equal footing with statutes passed through legislative processes and regulations issued by executive branch agencies; the principle of stare decisis means that past court rulings bind lower courts and future judges to assure that similar cases reach similar results.

The laws of a country govern many aspects of social life, from civil rights to criminal justice and the regulation of natural resources. The legal system also imposes restrictions on the activities of private corporations, such as those providing energy, gas and water services to its citizens. These private companies are bound by a variety of laws, depending on their size and the industry involved.

Among the most important functions of law are those of keeping the peace, maintaining the status quo and allowing for orderly social change. Some legal systems are more effective than others at serving these goals. For example, an authoritarian government may keep the peace and maintain the status quo, but it might oppress minorities or political opponents.

Oxford Reference offers comprehensive, authoritative coverage of the law as it is practiced in different countries and communities worldwide. It contains more than 34,000 concise definitions and in-depth, specialist encyclopedic entries covering topics from criminal law, family law and tax law to property law, international law, human rights law, and major debates in legal theory. This resource is ideal for researchers at every level, from students and professionals to academicians and general readers interested in law. It can be accessed online or in print. See also: legal history; jurisprudence; and the articles on censorship; crime and punishment; and war.