Law is the system of rules a society makes and enforces to regulate behavior, determine rights, and settle disputes. It can be state-enforced by a legislature, like a parliament or congress, elected (chosen) by the governed peoples; by a single legislator or executive, resulting in statutes; or established by judges through case law, particularly in common law jurisdictions. Private individuals can also create legally binding contracts.
There are many different areas of law, from a wide range of fields such as family law and criminal law to a variety of specific types of laws such as aviation law, bankruptcy law, contract law, maritime law, medical jurisprudence, and corporate law. One of the most interesting is tort law, which deals with injuries to people and their property. Another fascinating area is constitutional law, which sets the framework of a country, and immigration and nationality law, which deal with the right to live, work and gain citizenship in a nation-state.
Laws may be based on principles or on practical experience. The principle of stare decisis, for example, states that courts should follow earlier rulings on similar cases, unless there is a clear reason to do otherwise. The practical experiences that form the basis of a law often have to do with things such as felt necessities, popular moral and political theories, intuitions of public policy, avowed or unconscious prejudices, or social changes. The question of whether law should be a tool for advancing certain societal interests, and how those interests should be defined, is the topic of much debate.