Law is the set of rules that regulates human behaviour. It is enforceable by governmental institutions or by private individuals. It can be created by groups through a legislative process that creates statutes; by decree or orders issued by the executive branch that result in regulations; or by judicial decisions, which are established through the courts and known as common law. These laws are designed to keep society in order, prevent crime, provide justice and promote economic growth.

While the precise definition of law is contested, it is generally accepted that law encompasses a system of rules and codes of conduct that are enforced through coercion or threat of force, and that it applies to everyone regardless of status or wealth. It governs the interactions between citizens and the relationship between government and people, as well as between different levels of government, corporations and international bodies.

Legal scholars, practitioners and philosophers have debated the nature of law for centuries. In modern times, legal theory has been shaped by philosophers such as John Austin and Max Weber, while a range of social sciences have contributed to the understanding of law.

A key aspect of the law is that it protects against anarchy and the Hobbesian war of all against all by establishing a rule of law that applies to all citizens, even those in government. The rule of law also allows for a degree of certainty about the legal consequences of actions that helps enable planning and coordinated action over time. This is possible because laws are clearly defined and consistently applied.

The practice of law can be highly specialised and involves the study of a wide range of subjects. Contract law is central to commercial partnerships, whilst property law covers personal and real estate. Criminal law concerns the rights and duties of citizens, and is governed by civil procedure, which governs how cases are tried and heard, and substantive law, which covers the specific legal rights that can be asserted.

The practice of law is regulated by state, provincial and national governments and by independent professional regulating organisations (e.g. bar associations, bar councils and law societies). Lawyers are often qualified by completing a professional qualification course that results in a Bachelor of Laws or Bachelor of Commerce, and can be authorised to practise by undergoing a process of registration with the relevant regulatory body. They must also abide by the law and be a person of good standing in the community. They must also abide by the code of ethics established for their profession. These codes and standards are largely codified in legislation, but can also be found in other sources such as the Code of Conduct for Members of Parliament. Alternatively, some lawyers may have special qualifications that are not formalised in law. These may include a doctorate in law or a Master of Laws. Some are also accredited mediators. The use of these qualifications and credentials is a means of ensuring that the practice of law is conducted fairly and with integrity.