Law is a system of rules that are enforced by a government or other authority. These rules regulate behaviour, settle disputes and provide punishments. It is also a rich source of scholarly inquiry in areas such as history, philosophy, economic analysis and sociology, as it raises important issues concerning justice (proper distribution of privileges/burdens between members of a society) and ethics (moral standards).

Law governs the rights and responsibilities of people. It is usually divided into civil and criminal laws. Criminal law deals with conduct that is considered harmful to social order and provides for the punishment of the guilty party. Civil law provides for compensation when someone has been harmed, such as through an automobile accident or defamation of character. Civil laws include labour, property and family law. Laws can also regulate activities such as advertising and gambling.

Legal scholars have various definitions of law. It is generally agreed that law must be clear and accessible to ordinary citizens, and that it should allow for adjustment to changing circumstances. It should also be based on a rational and consistent principle, with the principles of supremacy of law, equality before the law and its impartial application. It must also be transparent, and involve public participation.

A key idea in modern thought on law is the idea of the Rule of Law. This is a concept that requires governments to respect fundamental human rights, freedoms and liberties in the course of governing their citizens and managing their economies. It is a concept that has evolved over the centuries from the ancient Greek idea of democracy and the Roman ideal of a republic.

This ideal has been reshaped by Max Weber and others, who have discussed the nature of power in a democratic society. They have pointed out that the extension of state authority into areas of life that were once left to private groups or communities creates problems of accountability that were not previously recognised.

Laws that extend state control over everyday activities need to be clear, fair and just. They should ensure that private and public institutions are accountable to the law, and that they do not discriminate against or favour anyone. They should also be consistent with international human rights standards.

The practice of law is usually overseen by a governing body, such as a bar association or professional council. Lawyers achieve their distinct identity as professional legal practitioners through specific and rigorous legal procedures such as the successful completion of a qualifying examination and being admitted to the bar. Law is also a subject of study for academics who research the development of legal systems and examine issues such as the impact of culture on laws. Law is a popular career choice for many young people, and it is a major subject of study in universities and colleges around the world.