Law is the system of rules and regulations that a society or government creates to govern the actions of its members. In many societies, the police and the courts enforce these laws, punishing people who break them with fines or jail time. Most countries have a constitution that sets out the overall framework for their law, and then make other laws to deal with specific matters. Private individuals also have their own legal systems, including contracts and agreements. The study of these different systems is called legal science.

The precise nature of law is a matter of long debate. Some see it as a set of enforceable rules for human conduct, others as a code of morality or even a divinely ordained order of the universe. Regardless of its nature, law is an essential part of all modern societies.

A central problem in studying law is the question of how it is created and enforced. This question is important because it explains much about a country’s political system and its culture. It also helps to explain why some countries have more stable democracies than others, and why revolutions against existing political-legal regimes occur periodically around the world.

Law is broadly categorized as civil law, criminal law, constitutional law, international law, administrative law, and family law. Civil law involves disputes between individuals, such as divorce proceedings or lawsuits for damages. Criminal law deals with offences against the state, such as murder or larceny. Constitutional law deals with the fundamental principles and limits of a nation-state’s authority. Administrative law covers the activities of government agencies.

Business law includes commercial and banking laws. Banks and other financial institutions have their own sets of rules, known as regulatory law. In addition, the specialized fields of intellectual property law protects things like art, music and literature with a kind of law called copyright; patent law covers inventions; and trademark law covers names used to identify a company or product.

The broader category of law also encompasses the rights and obligations people have toward each other, their possessions and the environment. Environmental law, for example, protects the air and water quality. Contract law regulates agreements between people for the sale or transfer of goods and services. Property law defines a person’s rights and duties toward land or buildings (real property) and personal possessions such as clothing, books and cars (personal property).

In the modern world, most people are required to obey the law if they want to live in peace with their fellow citizens. However, some people try to escape the constraints of the civil law by committing crimes against the state or their neighbors. These crimes are the subject of criminal law, which can result in imprisonment or death. Other kinds of violations of the law include terrorism and war crimes. International law is a separate branch of law that deals with the rights of nations to control their internal affairs and trade with other states.