Law provides a rich source of scholarly inquiry into legal history, philosophy, economic analysis and sociology. Law also raises important and complex issues concerning equality, fairness, and justice.

"In its majestic equality", said the author Anatole France in 1894, "the law forbids rich and poor alike to sleep under bridges, beg in the streets and steal loaves of bread." Writing in 350 BC, the Greek philosopher Aristotle declared, "The rule of law is better than the rule of any individual." In a presidential democracy, the constitution is sovereign and the central institutions for interpreting and creating law are the three main branches of government, namely an impartial judiciary, a democratic legislature, and an accountable executive. In parliamentary systems, the legislature is sovereign and appoints one of its members as the executive (often called the prime minister). The judicial branch is under the parliament. All legal systems deal with the same basic issues, but jurisdictions categorise and identify its legal subjects in different ways. A common distinction is that between "public law" (a term related closely to the state, and including constitutional, administrative and criminal law), and "private law" (which covers contract, tort and property). In civil law systems, contract and tort fall under a general law of obligations, while trusts law is dealt with under statutory regimes or international conventions. International, constitutional and administrative law, criminal law, contract, tort, property law and trusts are regarded as the "traditional core

subjects", although there are many further disciplines. Constitutional and administrative law govern the affairs of the state. Constitutional law concerns both the relationships between the executive, legislature and judiciary and the human rights or civil liberties of individuals against the state. Most jurisdictions, like the United States and France, have a single codified constitution with a bill of rights. A few, like the United Kingdom, have no such document. A "constitution" is simply those laws which constitute the body politic, from statute, case law and convention. A case named Entick v Carrington illustrates a constitutional principle deriving from the common law. Mr Entick's house was searched and ransacked by Sheriff Carrington. When Mr Entick complained in court, Sheriff Carrington argued that a warrant from a Government minister, the Earl of Halifax, was valid authority. However, there was no written statutory provision or court authority. The leading judge, Lord Camden, stated that,

The fundamental constitutional principle, inspired by John Locke, holds that the individual can do anything but that which is forbidden by law, and the state may do nothing but that which is authorised by law. Administrative law is the chief method for people to hold state bodies to account. People can apply for judicial review of actions or decisions by local councils, public services or government ministries, to ensure that they comply with the law. The first specialist administrative court was the Conseil d'Etat set up in 1799, as Napoleon assumed power in France