This role was largely created by the landmark U.S. Supreme Court case of Morrissey v. Brewer, in which the Court indicated a parole officer could conduct the preliminary hearing of a two-step hearing process possibly leading to a parole revocation and return to prison. The role of a hearing officer is a substantial departure from normal officer functions of supervision and presentence investigations. Probation and parole officers are typically involved with people whose guilt has already been established. As a hearing officer, however, presumption of innocence rather than guilt must be the officer's posture. A hearing officer must also sit in judgment on colleagues' allegations of probation and parole violations and remain objective and fair to both sides. Another challenge is to deal diplomatically with attorneys accustomed to the court's adversarial format but unfamiliar with the more limited due process procedures of an administrative hearing. Overall, probation and parole officers have apparently met the challenges of functioning as revocation hearing officers. After more than 15 years, the hearing officer's role has not been successfully challenged in the U.S. Supreme Court. The literature on probation and parole officers' roles, however, gives little attention to this aspect. 19-item bibliography.