An appeal is a process of law by which the cases are reviewed where parties can request for an official change to an authorized decision. Appeal laws can act as a process of illuminating and interpreting the the law and also as a process for mistake rectification. Common law countries did not incorporate an affirmative right to appeal into their jurisprudence until the 19th century, although appellate courts have existed for thousands of years. Most litigants appeal final orders and judgments from lower courts, although some courts permit appeals at preliminary stages of litigation. Appellate courts do not carry out independent fact-finding or investigate. But there are many legal systems which at their fundamental base require appellate courts to questions of law-de-novo. But instead of doing this in every instance, unless some error occurred during the fact-finding process, appellate courts will generally defer to the record established by the trial court. In many jurisdictions, the litigants are provided a statutory and constitutional right to appeal against unfavorable decisions. When an appellate court grants a party’s petition for review or petition for certiorari the appellate process usually begins. As per appeal laws, appeals are usually presented to a panel of judges or to a single judge, rather than a jury which happens in the case of trials. Parties are generally required to submit legal briefs to present their point of view, before making any formal argument. Appellate courts may also endow consent for amicus curiae to put forward a brief in support of a particular position or a party. Parties often have the opportunity to present an oral argument to a panel of judges or a single judge, after submitting briefs. It is common for judges to ask questions during oral arguments, to attorneys for challenging their arguments or to press forward their own legal theories. The appellate courts after deliberating in their chambers will issue formal opinions that decide the legal issues presented for evaluation.

The appellate courts generally reverse, affirm, or vacate the decision of a lower court, when considering cases on appeal. In some areas, the courts serve a dual function where they consider both matters of the”first instance”, as well as appeals. There are also some jurisdictions which maintain a system of intermediate appellate courts, which are subject to the review of higher appellate courts. In a jurisdiction, the highest appellate court is sometimes referred to as a “court of last resort”.