Law is a set of rules that governs behavior and provides a framework for a society to ensure peace and stability. It provides protection for individuals, property and freedoms. It also provides punishment for people who break the rules and cause harm. Law is a complex concept and the subject of many books, debates and discussions. There is no one definition of law, as different legal systems and individual practitioners have a wide range of ideas and concepts about what the law is.

Nevertheless, there are a number of themes that appear in most discussion of law. These include the nature of law as a social institution, its role in satisfying social wants, and its normative dimension. The latter feature has been controversial. Hans Kelsen, for example, proposed that the monopolization of violence in society is what makes law distinctive and that this aspect explains its normativity. Twentieth century legal positivists, however, have tended to deny this claim and argue that coercion is not essential to the operation of law or pivotal to its fulfillment of social functions.

The function of the law varies from nation to nation, but it generally includes four core tasks: setting standards, maintaining order, resolving disputes and protecting liberties and rights. The principal areas of law include civil, criminal and international law. Civil law includes contract, torts and property laws while criminal law covers the offences against a state or individual citizens. International law involves the relationships among nation-states and their international organizations such as the United Nations.

In addition to these basic aspects of law, there are other specialized fields such as immigration and nationality law; labour law (studies the tripartite relationship between worker, employer and trade union); and family law. There is also a growing field called biolaw, which involves the intersection of law and the life sciences.

It is not possible to give a precise definition of law, as it varies by jurisdiction and even within a jurisdiction. Law is a broad concept that consists of a complex interwoven network of legal institutions and procedures, including courts, tribunals and regulatory agencies, and the professions involved in their creation and enforcement. The scholarly literature on law is vast and varied, reflecting the complexity of the subject and the diversity of approaches.

It is also important to note that law reflects and shapes society, and that the existence of law in a given country depends on the power structure and history of a nation-state. Some philosophers have argued that the legitimacy of law is contingent on whether or not it is established by popular consent and is able to respond to changing needs and new problems. Those who make this argument assert that a state that does not have the support of its citizens cannot maintain the rule of law and must reform itself. This view has been criticized by others who argue that the legitimacy of law depends on the extent to which it is compatible with human values and interests.