Law is a system of rules created and enforced by social or governmental institutions to regulate behavior. It is often regarded as a science, though its precise definition remains a matter of longstanding debate. The exact nature of law is disputed by different schools of thought, including positivism (a view that considers it to be a set of measurable objective phenomena) and structuralism (a view that sees it as an intangible entity formed from social and political arrangements).

Law has a complex relationship with the rest of society. It influences politics, economics, history and society in many ways. For example, it defines the relationships between individuals and between groups or communities and helps to establish a balance of power between them. The law also shapes how people use public resources, such as water or the air, and it provides a basis for regulating private businesses. It may also help to prevent the exploitation of people and the environment by making it illegal to exploit them for profit.

The law is usually a written document and can be divided into many categories depending on its purpose and content. For example, it can be a constitution, an act of parliament or a code. Laws can cover such areas as criminal law, administrative law, employment law and taxation. The law can also cover social issues such as property rights and equality, as well as economics such as supply and demand.

In addition to regulating interactions between people, law can regulate the activities of governments and large organisations. The law can also be used to provide a framework for research and development, such as by setting minimum safety standards for products and services. For example, the law can require that an airline carries life rafts or that a food manufacturer test its products for contaminants.

A particular feature of the law is that it is based on a system of authority and is authoritative from an ontological perspective. This means that laws are not viewed as being provable or causal, unlike statements in empirical science such as the law of gravity, and in social science, such as the law of supply and demand.

Laws can also be based on beliefs and traditions, such as religious or moral teachings. For instance, Islamic Sharia law is a system of laws governing the Muslim world. The law is also shaped by culture and by the customs and practices of the legal profession. For more information, see legal profession, legal education and legal ethics. A further topic is the relationship between law and power, which has been influenced by Max Weber and other thinkers. The articles below look at the different aspects of the law, from its nature to how it is implemented.