Law is a set of rules created and enforced through social or governmental institutions to regulate behavior and to settle disputes. It can be state-enforced, as in civil law jurisdictions or common law systems, or privately enforced, like in private contracts or arbitration agreements. It covers areas of life that range from terrorism to the way a court handles a case. It influences politics, economics and history and reflects the way in which power is exercised in societies. Max Weber reshaped thinking on the extension of the state, while legal philosophers such as Locke and Montesquieu have laid down ideas on the basis of which laws can be formulated.

The study of Law is called jurisprudence, and it has many sub-fields. The main three are criminal law, common law and civil law. Other fields include labour law, which deals with the tripartite industrial relationship between worker, employer and trade union; family law, which looks at the rights and duties of families; property law, which encompasses ownership and the acquisition of wealth; and international law, which concerns treaties, international organizations and war.

There are many different kinds of legal system, but most have a constitution that dictates the principles and procedures of the state, and this can be amended through legislation. The constitution sets out a state’s fundamental values, and it may also contain clauses that limit the state’s authority to certain activities or to protect particular individuals. There are also judicial review mechanisms, such as appeals and human rights tribunals, that can challenge the constitutionality of laws passed by a government.

Laws are generally created by a collective legislature or by one legislator, and codified as statutes, or they may be issued by the executive through decrees and regulations. In “common law” legal systems, decisions made by judges are considered to be law, and the doctrine of stare decisis means that previous decisions of lower courts bind future courts, so that a uniform set of standards is applied.

A law is a set of principles that governs how society should work, and it is a framework for how citizens are to behave. It is also a system of justice, and it is this aspect of Law that creates some of the most heated debates, over issues such as the need for diversity in judging classes and the extent to which judges should use their own sense of justice when considering cases. There are also ongoing debates about whether terrorism trials should be held in regular court rooms, or specialized courts designed to focus on the unique issues involved in such cases. The sensitivity of these issues means that Law has a deep complexity which is not easily found in other disciplines, such as empirical science (the law of gravity) or social science (the law of the market). It is this dimension that makes Law a fascinating and complex subject.