Law is the set of rules that a community or society recognizes as regulating the behaviour of its members. It can be created by a collective legislature and result in statutes, or it may be established by the executive through decrees and regulations or, as is more usually the case in common law jurisdictions, by judges through precedent (a doctrine known as stare decisis). Individuals can also create legally binding contracts.
The legal professions are concerned with advising people about the law, representing them in court and enforcing the law. They include lawyers, barristers, solicitors and advocates. In addition to these practitioners there are judges, prosecutors and public defenders. The study of Law also encompasses the fields of jurisprudence, legal history, philosophy, economic analysis and sociology.
Whether the world needs laws is a matter for political debate. Some of the most profound issues in this area concern such topics as the nature of power, equality and justice.
In most nation-states (as countries are called in international law), knowing the power structure of a country is an essential part of understanding its laws and legal system. This is especially important when considering how law is made and enforced. The political and economic power of individuals and groups in a country often determines what kind of laws are made and how they are enforced. In some places this power is concentrated in the hands of a few, which leads to the threat of revolution or revolt against existing authority.