Law is the system of rules that a community recognizes as binding and enforceable. It is the study of the way that a society regulates itself, enforcing its standards, and creating a balance between competing interests.

The practice of law involves the exercise of legal authority, either by private citizens or by government officials. The law is a set of principles that governs the behavior of individuals and of groups in a society, including rights, duties and responsibilities. The law is created and enforced by a centralized authority, such as a government or a court. It is the body of rules that defines and protects individual freedoms, such as the right to property, privacy and safety. The law also sets a common standard for fairness and justice.

The nature and extent of the rule of law varies greatly from nation to nation, and is highly dependent on the political structure of each country. For example, a government with an authoritarian style can keep the peace and maintain the status quo, but it may oppress minorities and other political opponents (see Burma under tyranny or Iraq under Saddam Hussein). On the other hand, a democratically elected government that is stable and provides equal access to the justice system can promote social change, while ensuring that core human, civil and procedural rights are protected.

A central theme of the modern concept of law is the idea that the state must be held accountable by its citizens, irrespective of whether the law is good or bad. The notion of accountability is particularly important in the case of large and complex institutions, like military forces, policing agencies and government bureaucracies, which can exert powerful influence over individuals’ daily lives, as illustrated by the way the U.S. government imprisoned the democratically elected leader of Myanmar, Aung San Suu Kyi.

In the United States, federal law typically focuses on areas where there was an express grant of power to the federal government in the Constitution, like the military, money, foreign relations (especially international treaties), tariffs and intellectual property (specifically patents and copyrights). However, Congress frequently passes statutes that are not specifically listed in the Constitution. These are incorporated into the United States Code, which is divided into broad subject areas, known as titles. These are then further subdivided into sections, paragraphs and clauses.

Law is a complex and diverse topic, encompassing numerous fields of study. Oxford Reference provides more than 34,000 concise definitions and in-depth, specialist encyclopedic entries covering this vast field. This online resource covers the major terms and concepts in law, from criminal to corporate, family to property, taxation to international. It also explains the development of laws and legal systems, and describes how they are governed and enforced in different countries and communities. It is the essential source of information for researchers and students of law, law enforcement, government, politics and society.