Law is a body of rules that regulates behaviour and enforces them through penalties, often administered by a controlling authority. Its precise definition is a subject of longstanding debate. In some systems, laws are based on natural and immutable principles, while others are based on human interpretation. Some legal systems, such as that of the United States, employ a common law system where laws are compiled from judges’ decisions on cases that have been brought before them, while other countries, such as Japan, employ a civil law system.

In any legal system there are layers of complexity that go into determining what the law is. The law is not a set of clear instructions on how to do anything, but rather a complex framework that judges use as guides when deciding cases. To determine the law on a particular matter, judges first have to ascertain the facts and any relevant statutes and cases. Then they must extract from these sources the principles, analogies and statements that the courts consider important to the case at hand. Finally, they integrate these factors to decide what the law is on that matter.

A person who practices law, or studies it, is called a lawyer. Lawyers have many different careers. Some are employed by government, such as the police force or military, whilst others are in private practice, defending clients against criminal charges or representing companies in commercial disputes. Many lawyers are also lecturers or researchers, writing books and articles about the law. Those who are successful at practice tend to be very hard working, and are usually self-motivated.

Regardless of the precise definition of law, it is generally agreed that there are several functions that it serves: to keep the peace, maintain the status quo, protect individuals against majorities and minorities, preserve rights and enable social change. The extent to which a country’s laws serve these functions is, however, a question of politics and power. A government that is unstable or authoritarian may not fulfil these functions, and revolts against such governments are commonplace. Moreover, the modern extension of state power through policing and bureaucracy poses special problems that earlier writers such as Locke or Montesquieu did not anticipate.

The idea of a rule of law, traceable to ancient scholars, resonates in most legal traditions. It is a concept that combines laws, institutions, norms and community commitment to deliver four universal principles: accountability, just law, open government, and accessible and impartial justice. The rule of law is a foundation for healthy societies and is essential to sustainable development. In a world where law is increasingly global, the rule of law needs to be made more inclusive and transparent. This is a challenge that all governments, and all citizens of the world, should embrace.