Law is a set of rules that a society or government develops in order to deal with crimes, business agreements and social relationships. It can also refer to the people who work in this system, including lawyers and judges.
The precise nature of law is a matter of longstanding debate. It has been variously described as a science, an art and as justice. Law serves many purposes, but its four principal ones are establishing standards, maintaining order, resolving disputes and protecting liberties and rights. Law is unique among the sciences and disciplines in that it has both a normative and prescriptive character. This means that it states what people ought to do or not do, as well as regulating what they may require of each other and what they must or must not allow from others (or vice versa).
Legal systems are diverse worldwide, but can be broadly divided into civil and common law. Civil law focuses on property and personal relations and is based on sources recognised as authoritative, usually legislation (including statutes or constitutions) and case law. Codification has been a key feature of civil law, with the Napoleonic and German Codes being notable examples.
Criminal law is a broader field that deals with offences against the state and includes such things as murder, robbery and theft. It is primarily legislative, but leaves the judiciary considerable room for interpretation and creative jurisprudence. A common theme is a defence based on public interest or morality, allowing the accused to avoid punishment for their crime.
Commercial law is an area encompassing such areas as company law, insolvency, bankruptcy and tax laws. It can be very complex, and its origins date back to the medieval Lex Mercatoria, which emphasised freedom of contract and the alienability of property. The modern law of agency, contracts, insurance and bills of exchange owe their roots to this.
Labour law concerns employment contracts and issues related to unionisation. It can be very complex, and the rules are constantly changing as the workforce becomes increasingly specialised.