A set of rules created and enforced by social or governmental institutions to regulate behavior and to protect human rights. Its precise definition is a matter of longstanding debate and it has been variously described as a science and as the art of justice. The rule of law requires that government and private actors are held accountable for their actions, that laws are clear and publicized, that they are stable and applied evenly, that people have access to justice, and that the institutions and processes by which justice is delivered are accessible, fair, and efficient.

Law is a significant source of scholarly inquiry in such fields as legal history, philosophy, economic analysis and sociology, as well as an increasingly important area for business and international affairs. The study of law also raises many complex and difficult issues concerning equality, fairness and justice that are of vital importance to the general population.

There are four principal categories of law: criminal, civil, administrative and constitutional. Criminal law involves the punishment of conduct deemed harmful to society. Civil law addresses lawsuits between individuals or organizations. Administrative law deals with the issuance of regulations and permits for businesses or activities. Constitutional law deals with the interpretation of a country’s constitution.

The field of law is a vast one, covering such topics as torts (the compensation awarded when someone’s property or personal rights are harmed) the laws governing divorce proceedings, and the laws relating to social security benefits. Tax law includes regulations governing value added tax, corporate taxes and personal income tax. Banking law is concerned with the legality of financial transactions. Space law is a relatively new field addressing the legality of activities in Earth orbit and outer space.

There are also several specialized areas of law, such as admiralty law, which covers the law of shipping and nautical navigation; intellectual property law, which covers copyrights and trademarks; and environmental law, which covers the regulation of pollution. There is also an extensive body of case law, which consists of the decisions of courts on particular issues. There is a practice called “stare decisis,” which means that the decision of the higher court is binding on all lower courts, and this is considered the highest authority in a case. Finally, there is the common law of evidence, which sets out how legal evidence should be presented and what it may consist of. This is the system that underlies English law and much of continental Europe. There are other legal systems, such as those of the United States, Australia and India, which are based on different legal traditions. In addition, there are several regional and international treaties and conventions dealing with specific aspects of law. These treaties are sometimes referred to as customary law. A number of other international treaties deal with the status and rights of aliens. There is also an extensive area of international humanitarian law.