An appeal is a substantive right created by statute enabling a party to seek to set aside or vary an order. The conferring statute determines the nature of an appeal, which typically falls into one of three types: appeals by way of rehearing, appeals by way of hearing de novo and strict appeals (stricto sensu). Australian court systems have multiple levels of jurisdiction. Each level, with the exception of the High Court, generally has an avenue of appeal. The scope and nature of the appeal depends upon the terms of the statute creating the right of appeal. Appellate courts have wide powers to affirm, vary, or reverse judgments under appeal. Other powers include sending a case back for a retrial, setting aside jury verdicts, and granting a retrial. Appeals are commenced by a notice of appeal, which briefly states the grounds of the appeal. In some cases leave to appeal is required. The appeal court will require the appellant to prepare an appeal book or record, including pleadings, affidavits, orders and transcripts of evidence. Appeals may also have related applications. Examples include seeking a stay of execution pending an appeal, security for costs, leave to appeal and an application for an extension of time in which to file or serve a notice of appeal.There are many substantive bases upon which appeals are brought. The most common include errors of law, errors in the exercise of a discretion, incorrect findings of fact, incorrect inferences drawn from facts, excessive or insufficient assessments of damages and misdirection of a jury by a trial judge. Considerable difficulty arises in relation to the admission of fresh evidence available at trial, and to a lesser extent where a new point arises after judgment. New points and objections may also arise before judgment.Appellate courts have the power to grant a new trial where there has been a substantial wrong or miscarriage of justice. New trials tend to be avoided due to the duplication of costs incurred in rehearing the evidence. Appeals are an essential process for ensuring consistency and maintaining the high quality of the Australian judicial system.