Law consists of the set of rules that a country or community recognises as regulating the actions of its members. It shapes politics, economics and history and mediates relations between people in many different ways. Its creation may be influenced by a written or tacit constitution.

The term law also encapsulates the discipline and profession that studies this system of rules. There are several distinct branches of the field:

Contract law regulates agreements to exchange goods or services, whether buying a bus ticket or trading options on a derivatives market; property law determines people’s rights and duties toward their tangible properties (real estate), or personal possessions such as cars, computers and jewellery; and criminal law governs offenses against society at large – from murdering another person to defaming someone. Other branches include administrative law, environmental law and intellectual property law.

Depending on its political regime, law can serve a variety of purposes: it may keep the peace and maintain order, protect minorities against majorities, prevent social change or foster it. Some legal systems serve these purposes better than others: autocratic regimes may keep the peace but they often oppress minorities and restrict freedom of speech and assembly, whilst democratic governments usually foster peaceful and orderly social change. Law is also used to promote human rights. Lastly, it can establish standards and ensure accountability of both the government and private actors. The concept of the rule of law, traceable back to ancient scholars, resonates in most major legal traditions.