In law, something (e.g., testimony, documents, or physical objects) presented at a judicial or administrative proceeding for the purpose of establishing the truth or falsity of an allegation of fact. To preserve legal due process and to prevent the jury from being misled, an extensive body of rules has sprung up regarding the handling of evidence. In the U.S., all federal and many state courts adhere to the Federal Rules of Evidence, which covers such elements as types of evidence, admissibility, relevance, competency of witnesses, confessions and admissions, expert testimony, and authentication. Most evidence received at trial is in the form of verbal statements of witnesses, who are subject to questioning by attorneys from both sides. Two important categories of evidence are direct evidence, which is offered by a witness whose knowledge of a factual matter is firsthand (as through sight or hearing), and circumstantial evidence. See alsoexclusionary rule.