The Administrative Procedure Act (APA) enables individuals dissatisfied with agency action to challenge such action in federal court under standards that, depending on the type of action, range from “arbitrary and capricious” to “unreasonabl[e]”. The evidence that courts consider when rendering APA judgments is “the whole record” from the agency. Under the APA’s text, structure, stare decisis, history, and as a matter of practicality, “the whole record” means all materials considered or relied upon by the agency, as reflected in the record presented by the agency to the court. If an APA petitioner can make a strong showing that the agency’s record is missing documents that properly belong in the record, then she overcomes a strong presumption of agency regularity and may include those documents in the administrative record. “[T]he whole record” engenders significant confusion and inter-decisional inconsistency among litigants and courts. The APA does not define the term. Although scholars have for years described the legal landscape of record “completion” and “supplementation”, and in the absence of Supreme Court precedent, this article is the first to critically analyze the nuances of the APA record rule and why some litigants and courts are misapplying the law.