Law is a set of rules created and enforced by social or governmental institutions to regulate behavior and protect people from harm.[1] Its precise definition is a matter of longstanding debate. It serves many purposes, but four principal ones are establishing standards, maintaining order, resolving disputes and protecting liberties and rights.

Law can be made by legislatures in the form of statutes; by the executive branch through decrees and regulations,[2] or established by judges in cases with similar facts and circumstances as a precedent [3]. It may also be created by private individuals through legally binding contracts.[4] Some laws are specific to certain groupings of people, such as the rights of minorities or children. Other laws apply to all citizens.

Other important features of the law include procedural and evidentiary issues. The rules governing how to conduct a trial, the evidence that must be presented and its admissibility are examples of procedural law. Criminal law includes the rules relating to arrest, prosecution and punishment of perpetrators of crimes. Evidence law involves the collection and analysis of data and information for use in court. Evidentiary rules include the requirement that witnesses be sworn in and that testimony be based on credible, reliable and relevant evidence.

Several theories about the nature of law have been developed. Hans Kelsen formulated the pure theory of law, which defines it as a normative science that describes what should occur rather than what must happen. Others, such as Jeremy Bentham and John Austin, used utilitarian theories of law, which emphasized that it reflects the needs of society. Natural lawyers such as Jean-Jacques Rousseau argued that the law reflects innate principles of morality and immutable natural laws.