Law is a system of rules and regulations enforced through social or government institutions to ensure that all members of a society adhere to certain principles and practices. Laws can be imposed by a collective legislature, resulting in statutes; by an executive, generating decrees and regulations; or by a judge, creating precedent (common law jurisdictions).
The legal system serves several purposes: establishing standards, maintaining order, resolving disputes and protecting liberties and rights. Even in well-ordered societies, people disagree and disputes arise, such as when two individuals claim the same piece of land. The law resolves these conflicts peacefully by determining the rightful owner of the property.
There are many other purposes served by the legal system: regulating business and finance; settling personal injury lawsuits; deciding alimony and child support; and determining criminal punishment. The field of law also contains specialized branches such as administrative law, which deals with how agencies act; criminal procedure, which outlines how trials are conducted; and evidence law, which defines what materials are admissible in court.
The study of Law is highly interdisciplinary, drawing on fields such as history, philosophy, sociology and economics. In the modern world, the extension of state power to control the daily lives of citizens raises complex questions about equity and fairness that earlier writers such as Montesquieu and Locke could not have foreseen. Moreover, laws are constantly evolving as scientific research uncovers new information that can change or improve upon previous understandings of the law.