Law is the set of rules that regulate people’s lives, including their rights and duties. It has various purposes, but the most important are establishing standards, maintaining order, resolving disputes and protecting liberties and rights. The precise definition of law has long been debated. Laws can be state-enforced, for example through statutes; or privately created and enforceable by contracts.

The laws that govern a society can vary greatly, reflecting the cultures and traditions of different countries. For example, Indian law reflects Hindu and Islamic influences, while in Western countries English law dominates. Law can be created by a group legislature or a single legislator, resulting in statutes; by the executive through decrees and regulations; or through judicial decisions that create precedent, a common system in many countries. Private individuals may also create legally binding contracts and arbitration agreements, which are alternative ways of resolving disputes to standard court litigation.

Some philosophers, such as Jeremy Bentham, have argued that the purpose of law is to promote social welfare by creating and enforcing rules that must be followed, regardless of whether those rules are good or bad. This understanding of law is known as legal positivism. Others, such as Jean-Jacques Rousseau and Thomas Aquinas, have argued that law reflects essentially moral principles that are unchanging, such as the principle of due process (fundamental fairness in government actions) or the principle of nonviolence. In addition to contract, property and criminal laws, other major areas of law include labour law, medical jurisprudence, administrative law, family law, maritime law, aviation law, and commercial law.