Law is the set of rules and regulations that are enforced by a government in order to maintain order, ensure justice, and promote social change. While the precise definition of law is often contested, almost all theorists agree that the primary function of law is to secure justice.

The legal system is comprised of a complex interplay between federal and state laws, treaties, administrative agency regulations, court decisions, and local custom and policies that are enacted and enforced by the community at large. The precise structure of a nation’s legal system differs widely from one country to another. However, many of the same basic principles apply throughout most of the world.

Law is a central topic of scholarly study in the fields of history, philosophy, sociology and economic analysis. It is also the source of numerous political and philosophical debates. For example, some philosophers have argued that the concept of law is not an end in itself but rather a means to the end of securing justice. Other scholars have argued that law is an instrument for regulating behavior and that it has a normative and prescriptive character (i.e., it tells people how they should behave and what they ought to do). Others have emphasized that the law is an expression of the will of a sovereign and that it orders and permits and forbids, announces rewards and punishments. Still others have emphasized the importance of a “flow” model of law, whereby an individual’s rational decision is based on their prediction of how their own narrative intersects with an external reality that is shaped by other peoples’ narratives.