Law is a set of rules established and enforced by social or governmental institutions to govern behavior. It may be enacted by a group legislature, which results in statutes; by the executive, through decrees and regulations; or through judicial decisions, called case law, which is often binding on other judges in a jurisdiction. Individuals may also create legal agreements and contracts to resolve disputes, as in the case of a contract law or tort law. The precise nature of law is a subject of long-standing debate, with many different schools of thought.

The law has several purposes, which can be broadly categorized as establishing standards, maintaining order, resolving disputes and protecting liberties and rights. The effectiveness of a law depends on its ability to accomplish these goals, and some legal systems are better at doing so than others. For example, an authoritarian regime may keep the peace and maintain stability, but it can be oppressive of minorities or political opponents.

Some of the most important fields of law focus on specific issues. For example, immigration law deals with the rights of people to live in a country that is not their own and to acquire or lose citizenship, while family law addresses issues such as marriage, divorce and custody of children. Criminal law, civil procedure and evidence law each address the rules that must be followed as a case is tried in court or appealed to higher courts.

While these field-specific laws are essential to a functional legal system, the most basic purpose of any law is to control human conduct. This is why some legal scholars have emphasized the need to view law as an instrument of social control.

One of the most influential theories of law was developed by Roscoe Pound, who defined it as “a tool for social engineering, in which the primary goal is the satisfaction of social wants.” In this view, the function of the law is to control society by imposing socially desirable behaviours on its citizens through coercive means.

A variety of legal fields can be studied, depending on a person’s interests or career aspirations. For example, contract law deals with the standard form of a commercial transaction, while tax law is about how to legally pay taxes. Tort law provides a remedy for people who have been wronged by another party, whether it’s in an accident or by defamation of character. A law degree can lead to careers in the judiciary, government, the private sector and academia. It is important for people interested in a particular field of law to study the different approaches and arguments in order to gain a fuller understanding of what the law truly is.