Law is a set of rules that governs human conduct and determines rights, duties, expectations and obligations in society. It also sanctions rewards and punishments. A law is a formal expression of legislative will and is usually enacted by a legislature, such as a parliament or council. It can be interpreted and enforced by a judiciary, such as a court or tribunal. The term ‘law’ can also be used to refer to a legal profession, such as barristers or lawyers, or to the system of lawmaking in a country.

There are many different types of laws and systems of law around the world. They differ in the languages and traditions that they embody, but all are designed to help people live together in a way that is safe and fair. In some countries, law is written down and codified in a constitution, but in others it is customary rather than statutory. In either case, law forms an important part of a country’s identity and serves as the basis for all other systems of government.

The law shapes politics, economics and history in a variety of ways. It defines the relationships between people and between a state and its citizens, and it can serve as a mediator in those relations. Some people have criticized the idea of law as nothing more than power backed by threats, but it is possible to argue that, even if that were true, the fact that there are laws and that they can be enforced means that individuals do not feel completely at the mercy of those in authority.

Some areas of law are governed by federal laws that preempt, or supersede, all local and state law. Other areas have a mixture of state and federal laws, and in still other areas, there are no specific laws but only a common sense understanding of what is reasonable.

In addition to the broader topics covered by this article, the law can be studied from the viewpoint of legal institutions, practice and theory. For example, the study of legal institutions includes an examination of judicial structure and the role of law in the economy, while a legal theory looks at how law is made and how it is enforced.

Law can be studied as an academic subject at university level, with students often taking courses such as constitutional law and criminal justice. In addition, there are a number of specialist fields of law, such as environmental, family and intellectual property. Each of these has its own journals and books, and there are a range of careers available to those who specialise in them. For example, a graduate who studies environmental law can work in the environment, or they may choose to specialise in intellectual property and go into business or consultancy. Legal services are increasingly important in the modern economy, and this has led to a growing demand for lawyers. Lawyers are employed by a wide range of businesses to give advice about legal issues and represent clients in the courts.