Law is a complex field, but one of its principal functions is to establish standards, maintain order, and resolve disputes. It also protects individuals and groups from tyranny by those with military or political power, thereby promoting freedom and democracy. Yet, many nations still do not succeed at these vital tasks. Despite the difficulties, revolutions are still common, with people striving to have more democratic control of their government and to gain rights they feel are denied them.

The precise definition of Law is a matter of debate, but it has been generally agreed that law is a system of rules and principles enforced by a government or other authority to regulate behavior. This system of rules is called a legal system and it can be compared to a code or statute book in that its contents are clearly organized by subject matter and its provisions are easily accessible to citizens.

In some legal systems, a court’s decision in a particular case is binding on future cases under the principle of stare decisis. The resulting law is known as case law.

Other legal systems organize the law into a series of categories and rules that are more or less enforceable by courts. These are called civil law systems and they make up most of the world’s legal systems. These systems are based on concepts, categories, and rules largely derived from Roman law, sometimes supplemented by canon law and local custom.

These legal systems are characterized by a clear expression of rights and duties, a well-developed and to some extent transnational academic doctrine inspiring the judiciary, and an ability to adapt to changing social conditions through creative jurisprudence. They also typically feature a separation of powers and participation in decision-making by all parties.

A court’s judicial branch is responsible for the administration of justice and may include judges, clerks, marshals, interpreters, and bailiffs. A judicial branch may also have a staff of administrative personnel that assists in the day-to-day operations of a court, including screening applicants for pretrial release and monitoring convicted offenders on probation. The judicial branch may also employ public defenders to represent defendants who cannot afford lawyers in criminal trials and bystanders to provide assistance at crime scenes. In some jurisdictions, the term pro se means to present a lawsuit without an attorney; this is allowed for certain crimes in some states. In other jurisdictions, the term in forma pauperis means permission to sue without paying court fees based on claims of poverty or indigence. Appeals are heard by appellate courts. In the United States, an en banc appeal is one heard by all members of a circuit court’s panel of judges. In other countries, such appeals are usually heard by a smaller panel of three judges. In both civil and criminal trials, the person who brings a lawsuit is called the plaintiff or the defendant. The court in which a trial is held is the trial court.