Regardless of its origins, the term law has come to mean a set of rules that govern human interactions and activities. Laws are enforceable by social institutions such as courts. These laws are designed to protect the interests of people. Law also plays a central role in shaping politics, economics, history and society.

Law can be classified into three categories: civil law, common law and international law. Each of these systems has its own characteristic. Common law legal systems use the doctrine of precedent to bind future judicial decisions to past ones. The legal system of the United States is an example of common law. It includes the US Uniform Commercial Code, which codifies common law commercial principles.

Civil law systems are less detailed than common law systems. Usually, judicial decisions are less complex. In a civil law system, a court is writing to decide a single case, rather than a series of cases. The court may use argumentative theories, such as legal syllogism, to reach a decision. In civil law systems, the court may be influenced by constitutions.

The International Law Commission is an advisory body of the United Nations that promotes the progressive development of international law. Its members are experts in their respective fields. They consult with UN specialized agencies and prepare drafts on aspects of international law. The Commission also promotes the codification of international law.

The International Court of Justice (also known as the World Court) is the primary dispute-settling organ of the United Nations. It was founded in 1946 and has issued hundreds of judgments and advisory opinions. During its existence, the Court has considered more than 170 cases. A number of cases have been referred to special chambers. Most cases have been decided by the full Court.

The International Court of Justice has interpreted over 500 multilateral treaties. Its work has included the protection of the environment, combating terrorism and drug trafficking, and regulating migrant labour. It has also addressed issues such as international dimension and human rights law. The Charter of the United Nations calls on the Organization to promote the progressive development of international law.

A number of multilateral treaties are open for signature and ratification. The United Nations General Assembly is responsible for adopting many of these treaties. Some of the treaties include the Kyoto Protocol, which aims to reduce the adverse effects of climate change. It also includes the Treaty on Peaceful Uses of Outer Space. Increasingly, space law deals with issues such as commercialisation of space, property rights, liability and safety regulations.

Historically, the concept of “natural law” grew out of ancient Greek philosophy and connected to the notion of justice. It was revived in the 19th century through the writings of Thomas Aquinas. Although utilitarian theories remained dominant in law until the early 20th century, they are no longer the dominant theory.

Modern lawyers are required to have a degree from a legal institution, such as a Bachelor of Laws, Bachelor of Civil Law or Doctor of Laws. They also need to pass a qualifying examination to practice.