The law is a system of rules that regulates the conduct of a society and can be enforced by penalties. Law is a complex subject, as different societies have very different systems of law and different ideas about what the law should be. There are many books and debates about what the law is, but in general it refers to a set of principles created by a society that governs how that society is run. A legal system is a particular arrangement of laws that governs a society, and it can include common law, constitutional law, statutory law and regulatory law.
Most countries, including the United States, use a common law system. In this system, judges interpret the law by judging specific cases that come to trial. Judges’ decisions are then compiled into case law. In contrast, some nations, such as Japan, use a civil law system. This system has legislative statutes that outline what judges must do in a case and is more detailed. In a common law system, judges’ decisions are not binding on other courts in the same jurisdiction, but they do influence future case law by providing persuasive authority.
Another factor influencing the nature of laws is political power. Who controls the state and how political-legal power is exercised affects how laws are made and enforced. Revolutions against existing political-legal power and aspirations for democratic rule or greater rights for citizens are a recurring theme in human history.
Whether or not people agree on the content of the law, there are certain things that all legal systems must have in order to function properly. This includes a separation of powers, checks and balances, a free press, and transparency in the process of making laws. Generally, people must be able to trust that the laws are fair and are applied equally.
A legal system also must have the capacity to enact and amend laws. For example, when a legislature enacts a new law, it must be published as a public law and then may be amended by subsequent legislation. Many public laws are printed as slip laws, which are single sheets or pamphlets containing the text of the law. The majority of these laws are eventually compiled into a single volume called the United States Statutes at Large.
The practice of law is a highly regulated profession. Most jurisdictions require that lawyers meet education and training requirements, pass a bar examination or equivalent, be licensed by a government or independent regulating body, and maintain professional ethics. Lawyers are sometimes distinguished by titles of honor such as Esquire or Doctor of Law.