Law is a set of rules that form a framework to ensure a peaceful society and can be enforced by sanctions if they are broken. The precise content of laws varies across different countries and individuals, but a core element is that it should be clear, accessible, enforceable, stable and just. There is a wide spectrum of views on what exactly constitutes the law and there have been numerous books written on the topic. However, a common theme is that it is the duty of the state to regulate people and enforce standards that are considered fair.

The law is a source of inspiration and debate in fields such as legal history, philosophy, economic analysis, sociology, social science and political science. It raises fundamental issues about justice (the proper distribution of burdens and benefits within a community) and the role of authority. It is also an important tool for democracy, providing a means by which citizens can hold their government to account.

From a methodological perspective, the law has unique features which distinguish it from empirical sciences such as natural science (like the law of gravity) and social sciences such as sociology. A key feature is that normative statements in the law lack a descriptive or causal character which would allow them to be tested and verified as with empirical scientific laws such as those of gravity or social science theories such as those of Max Weber.

Laws have a number of purposes including establishing standards, maintaining order, resolving disputes and protecting liberties and rights. The scope and extent of the role that the law can play in a nation depends on the nature of the ruling political system. For example, a government with authoritarian characteristics can keep the peace and maintain the status quo but it may not protect minorities against majorities or provide for an orderly process of social change.

In general, the rules of a country can be categorised as civil law, criminal law and administrative law. Civil law is concerned with resolving disputes between private parties, for example a dispute over a property right or a contract. Criminal law covers conduct that is deemed to threaten social order, such as murder or robbery. Administrative law relates to the procedures that must be followed as cases are investigated and heard, such as evidence law involving what materials can be used in a trial or hearing. It also includes public policy which deals with broad policy areas, such as the environment or social security. These policies can be enforced by the courts. Alternatively, they may be implemented by an executive branch of the government.