Law is the set of rules created and enforceable by social or governmental institutions that regulate behavior. It shapes politics, economics, history and society in various ways and serves as a mediator of relations between people. Its precise definition is a matter of longstanding debate and it has been variously described as a science and as an art of justice.

The law exists in all societies and there are many different types of laws. Some of these include:

Contract law is the set of rules that governs agreements to exchange goods, services or anything else of value. It is the basis for most commercial transactions and covers everything from buying a bus ticket to trading shares on a stock market. Property law defines people’s rights and duties towards tangible property – land or buildings – as well as intangible property such as intellectual property, patents and copyright. It is the legal framework governing ownership and use of goods and services, from a bus ticket to a copyrighted work of art. It also outlines the rules and responsibilities for managing and disposing of property. Criminal law outlines crimes and punishments for them, while administrative law covers a variety of government functions such as taxation, licensing and regulation.

There are a number of distinctive features to law that set it apart from other scientific or social sciences. Firstly, it is normative and prescriptive, which means that it contains precepts about what people ought to do or not do based on an underlying belief system. Secondly, law has no means of empirical verification – unlike the laws of gravity or the principles of economics – because it is essentially an intellectual activity that depends on human minds and their mental operations.

Legal systems can broadly be divided into civil law jurisdictions, where a legislature or other central body codifies and consolidates their laws, and common law systems, where judge-made precedent is binding. In some cases, especially in former colonial territories, the civil law traditions of continental European countries are retained alongside other, indigenous legal systems such as Islamic Sharia law or Christian canon law.

In common law systems, judges’ decisions are recognised as “law” on an equal footing with statutes passed by parliament and regulations issued by the executive branch. The principle of stare decisis (Latin for ‘to stand by decisions’) means that a court’s decision in one case will bind judges in future cases deciding the same issues, in order to ensure consistency in judicial interpretation of the law. This contrasts with the civil law approach where legislative statutes tend to be more detailed and judicial decisions shorter and less reiterative. There are also a few religious law systems, where religious precepts act as the foundation for their laws. The most famous is the Jewish Halakha and the Islamic Sharia, which continue to be used in some communities.