Law is the collection of rules governing human society. It is also a concept, or framework, for legal systems, and it encompasses a wide range of laws: criminal, civil, property, administrative, intellectual, and commercial. It has an important role in human society, guiding us through the ethical and practical challenges of everyday life. Laws are formulated by individuals, organizations and governments and are subject to review and revision as the society changes.

The most fundamental function of law is to regulate behavior in a society, but its scope is wider than that. Laws can be created to encourage certain types of behavior, limit them, or prohibit others. They can be used to provide security for business transactions, promote health and safety, control pollution, govern elections, settle disputes, and much more.

Law can be broadly divided into two types: constitutional and statutory. Constitutional law is the basis of a nation’s government and the foundation for its institutions, and it can be amended or replaced as the needs of the people change. Statutory law is created by legislative bodies and is often more detailed than constitutional law.

Both constitutional and statutory law are part of the common law. In common law nations, decisions of courts are acknowledged as “law” on equal footing with legislative statutes and with regulations issued by the executive branch. A central feature of the common law is the doctrine of precedent, or stare decisis: court decisions that are similar in facts and law to a case currently before the courts are binding on those courts.

Other important aspects of law are the procedures for bringing and settling lawsuits, the principles of evidence and trial practice, and the rules of criminal procedure. The concept of jurisdiction also plays an important role: a court’s legal authority to decide cases, which can be limited or broad.

The principal functions of law are to keep the peace, maintain the status quo, preserve rights and liberties, protect minorities against majorities, promote social justice, and allow for orderly social change. Different nations have a variety of legal systems to perform these functions, and some serve them better than others.

A legal system must be able to function under a variety of circumstances, including times of war and peace. It must be stable, and its rulers must be legitimate, meaning that they must have the power to enforce their laws. Some governments, however, do not respect these basic requirements and fail to provide their citizens with peace and security. Revolutions are a result of these failures, and the aspiration for greater political-legal rights is a recurrent theme in many nations’ history. See also censorship; crime and punishment; judicial independence; and police. A rich academic tradition provides the inspiration for legal reasoning and legal analysis, and the law is a continually evolving entity.