Law is a complex subject covering all aspects of the relationships between people and between people and organisations. It includes the legal rights of citizens and the duties and responsibilities of public officials and businesses. Law shapes politics, economics, history and society in many ways. It regulates a wide range of activities, from the way people get married to how companies can advertise.
Different countries have different law systems. For example, the United States has a common law system where judges use decisions in previous cases to decide new ones. This is known as the doctrine of stare decisis. In civil law jurisdictions, the sources recognised as authoritative are primarily legislation—that is, statutes passed by government—and not case law.
The broadest categories of law are a) property law—which covers everything from who owns a car to the ownership of land; b) criminal law—which deals with the punishment of crimes; and c) administrative law—which is concerned with regulations in fields like water, electricity and banking. These laws are shaped by social, ethical and religious beliefs as well as by the needs of commerce and industry.
Lawyers are recognised as a distinct profession and are held to high standards. They have specific educational qualifications and pass a rigorous professional examination. In some countries lawyers are regulated by an independent governing body, such as a bar association or law society. The field is a dynamic one, with ongoing debates over such issues as whether judges should be above politics or not (see judging). Despite its complexity, law has a very simple purpose: to ensure that people live together peacefully. Even in the best of societies there are disagreements and conflicts, but they are settled by the law.