Law is a system of rules created and enforced by social or governmental institutions to regulate behavior. Its precise definition is a matter of longstanding debate, but the broad meaning is that it is a set of rules that governs the affairs of people and society. Law may be enacted by legislative bodies, resulting in statutes; by the executive, resulting in decrees and regulations; or through the judiciary, in the form of precedent established by judges. Private individuals may also create legally binding contracts, including arbitration agreements which provide alternative methods of dispute resolution to standard court litigation.

Law affects politics, economics and history in profound ways. It defines and shapes the environment of a country, and is an instrument for societal change and evolution. It can be used as a tool for social control, or to establish justice and equity. Law is also a field of study with its own academic disciplines and subfields, such as criminal law, administrative law, international law, constitutional law, and civil rights.

The laws of a country are shaped by a number of factors, such as the constitution (written or tacit) and the principles encoded in it. The system of laws can vary from region to region, as can the underlying culture. In a democracy, the people can vote on new laws through referendums, and the law is subject to amendment by a constituent body.

A country’s legal system is a complex web of laws, with its own traditions and influences. It may be based on religious precepts, such as Jewish Halakha or Islamic Sharia, or secular, such as ancient Babylonian law or the Code of Hammurabi. Modern Western countries generally use the common law, which places judicial precedent on an equal footing with statutes.

In many jurisdictions the law is enforced by a judiciary, which includes a bench of judges and sometimes a bar association. A judge resolves disputes between citizens, and determines the guilt or innocence of those who are charged with crimes. Some nations have a jury system where citizens, sworn on oath to investigate the facts of the case, find the verdict. Other types of cases are ruled on by administrative law officials, such as a labour board for workplace matters or an environmental agency for environmental violations. Transactional law is the study of legal issues involving business and money, while biolaw focuses on the intersection of law and the life sciences. Those who practice law are called lawyers. Other legal professionals include paralegals, clerks, and investigators. Some states offer special licenses to those interested in becoming a lawyer.