Law is a term which does not have a universally accepted definition, but one definition is that law is a system of rules and guidelines which are enforced through social institutions to govern behavior. Laws are made by governments, specifically by their legislatures. The formation of laws themselves may be influenced by a constitution (written or unwritten) and the rights encoded therein. The law shapes politics, economics and society in countless ways and serves as a social mediator of relations between people.

A general distinction can be made between civil law jurisdictions (including Canon and Socialist law), in which the legislature or other central body codifies and consolidates their laws, and common law systems (including Islamic law), where judge-made binding precedents are accepted. Historically, religious laws played a significant role even in settling of secular matters, which is still the case in some countries, particularly Islamic.

The adjudication of the law is generally divided into two main areas. Criminal law deals with conduct that is considered harmful to social order and in which the guilty party may be imprisoned or fined. Civil law (not to be confused with civil law jurisdictions above) deals with the resolution of lawsuits (disputes) between individuals or organizations. These resolutions seek to provide a legal remedy (often monetary damages) to the winning litigant.

Under civil law, the following specialties, among others, exist: Contract law regulates everything from buying a bus ticket to trading on derivatives markets. Property law regulates the transfer and title of personal property and real property. Trust law applies to assets held for investment and financial security. Tort law allows claims for compensation if a person's property is harmed. Constitutional law provides a framework for the creation of law, the protection of human rights and the election of political representatives. Administrative law is used to review the decisions of government agencies. International law governs affairs between sovereign states in activities ranging from trade to military action.

To implement and enforce the law and provide services to the public by public servants, a government's bureaucracy, the military and police are vital. While all these organs of the state are creatures created and bound by law, an independent legal profession and a vibrant civil society inform and support their progress[citation needed].

Law provides a rich source of scholarly inquiry into legal history, philosophy, economic analysis and sociology. Law also raises important and complex issues concerning equality, fairness, and justice. "In its majestic equality", said the author Anatole France in 1894, "the law forbids rich and poor alike to sleep under bridges, beg in the streets and steal loaves of bread." Writing in 350 BC, the Greek philosopher Aristotle declared, "The rule of law is better than the rule of any individual."

In a presidential democracy, the constitution is sovereign and the central institutions for interpreting and creating law are the three main branches of government, namely an impartial judiciary, a democratic legislature, and an accountable executive. In parliamentary systems, the legislature is sovereign and appoints one of its members as the executive (often called the prime minister). The judicial branch is under the parliament.[citation needed]