Law is a system of rules that binds all members of society. It serves four main purposes: establishing standards, maintaining order, resolving disputes and protecting liberties and rights. In modern society, these are accomplished through the courts and other government bodies.

A wide variety of legal systems exist, reflecting different cultures and historical contexts. However, all of them incorporate the principles of supremacy of the law, equality before the law and accountability to the law. These are the foundations for the rule of law, a principle of governance in which all public and private institutions, including the state itself, are subject to laws that are publicly promulgated, equally enforced and independently adjudicated. The state must also be capable of being held to account and demonstrate that it is transparent in its dealings with citizens.

The study of law is the discipline and profession concerned with the customs, practices and rules of conduct that are binding upon a community, as well as the system of courts in which such laws are interpreted and enforced. Lawyers are professionals who advise individuals and companies on the law, represent them in court and defend their rights and interests. They may also give advice and guidance on issues such as acquitting criminals, settling disputes and forming partnerships.

In addition to the standard legal principles, there are numerous fields of law, allowing for the study of a broad range of subjects. For example, contract law deals with agreements between two or more parties. Tort law covers damages resulting from wrongful acts, such as automobile accidents or defamation of character. The law of property determines the rights and duties of people toward their tangible possessions (such as land or cars), as well as intangible ones (such as bank accounts or shares of stock).

Another area of study is law as it relates to a specific group or social class, such as criminal, civil or labour law. This can help us understand how the law varies by socioeconomic status and how that relates to the rule of law.

Law can also be seen as a moral and ethical concept, with some of its laws seeming to reflect a moral stance against cruelty or other types of injustice. For example, the law against insider trading is designed to protect investors from using nonpublic information to gain an unfair advantage. Other laws, such as due process, are based on a principle of fundamental fairness and equity in the actions of government. These are a broader form of legal positivism, which has a different emphasis than the pure theory of law. However, many critics suggest that legal positivism is too limited in its conception of law. The debate continues about how much a judge’s own sense of what is right and wrong should affect their rulings, even if those judgements are not formalised into laws by a parliament or similar body. Similarly, the question is raised of whether a judge should be able to disapply a law that they feel is unjust.