Law is a system of rules and guidelines that governs the actions of people and businesses. Its main purposes are establishing standards, maintaining order and resolving disputes, and protecting liberties and rights. Law can be imposed by a sovereign authority, such as a government or corporation, or self-imposed through a code of ethics or a community’s values. It may be enforced by penalties, as in criminal law or civil disobedience.

Law covers a wide range of topics, including criminal law, contract law, constitutional law, property law, intellectual property law, environmental law and labor law. Each of these areas can be subdivided into more specific subjects such as family law, business law or international law.

The precise nature of law is subject to long-running debate. Theorists such as Max Weber have reshaped thinking on how laws are created and enforced, while modern academics have examined the extent to which law is influenced by morality or the will of a deity (natural law theories). Other scholars have challenged the idea that there is a universal law based on natural rights and the principles of fairness and equity, preferring to see the law as a tool for managing power rather than exercising it as an agent of social change.

Different countries have different legal systems, which vary in the way they process civil and criminal cases. For example, the United States has a common law system, where judges make up case law from their decisions on cases that come before them. This can be contrasted with countries with a civil law system, where statutes and other legislative documents provide the basis for courts’ decision making.

In the US, the Constitution sets out foundational law and Congress creates statutory law; both types of law are compiled in the United States Code, which is updated every six years. Federal courts may interpret statutes and other legislation; their interpretations carry the force of law under the doctrine of Chevron deference. State constitutions and legislatures often create their own statutory law.

Law can also be established by the collective action of a group, such as a trade union or a political party, resulting in a code of conduct. Private individuals can also create legally binding contracts, e.g., arbitration agreements, which can offer alternative ways of resolving disputes to standard court litigation. Other areas of the law include administrative law, which deals with how governments and businesses are run; labour law, which examines the tripartite relationship between worker, employer and trade union; and evidence law, which determines what materials are admissible in courts.