Law is the set of rules created and enforced by social or governmental institutions to regulate behaviour. It aims to ensure that members of a community adhere to the established values and principles encoded in their constitution, whether written or tacit, and protects individual rights and liberties. Laws can be enacted by a collective legislative process resulting in statutes, or by the executive through decrees and regulations, or by judges through precedent. In “common law” legal systems, judicial decisions are recognised as law on an equal footing with statutes and regulations. This doctrine is called stare decisis.

In contrast, the legal system in a country with a civil code is more regulated than in a common law country. A country with a civil law system may have a constitution that provides the overall governing structure, but also has statutory laws on specific topics such as property. Civil codes were introduced in the 18th century to enable merchants to trade across Europe with a single set of standards, rather than having to deal with the many splintered facets of local law. The Napoleonic and German Codes were the most influential civil codes. Today, there are signs that the old distinction between civil and common law is dissolving.

A lawyer is an individual who practices law and has a professional relationship with clients. Modern lawyers gain their distinct professional identity through specified legal procedures (such as successfully passing a bar exam), and are normally members of a legal profession, with membership overseen by an independent regulating body such as a bar association, bar council or law society. In addition, they have a specific academic qualification such as a Bachelor of Laws, Bachelor of Civil Law or Juris Doctor degree. Some lawyers use titles of respect such as Esquire to signify a higher status within their profession, and the title of Professor of Law to indicate they have an academic background in law.

The four main purposes of law are establishing standards, maintaining order, resolving disputes and protecting liberty and rights. It is generally acknowledged that the law should not impose unreasonable burdens on individuals or society, and it should be fair and accessible to all.

Law is an integral part of the functioning of any society, and it covers a broad range of subjects. For example, contract law regulates agreements between people to exchange goods and services; criminal law punishes crimes against the state, such as murder or rape; and tort law compensates victims for losses incurred from a wide variety of events, including car accidents or defamation of character. Other fields of law include administrative law; canon law; family law; forensic science; labour law; maritime law; medical jurisprudence; and property law. Law is an incredibly complex subject, and this article only scratches the surface. For more information, see the articles on civil and criminal law; constitutional law; family law; and canon law. For a critical discussion of current changes in the law, see this article.