Under the 'Administrative Remedy Procedure for Inmates' at federal correctional institutions, a prisoner may 'seek formal review of a complaint which relates to any aspect of his imprisonment.' When an inmate files a complaint or appeal, the responsible officials are directed to acknowledge the filing with a 'signed receipt' which is returned to the inmate, to 'conduct an investigation,' and to 'respond to and sign all complaints or appeals.' The general grievance regulations do not provide for any kind of hearing or for the granting of any particular type of relief. The procedure includes rapid filing and response timetables. An inmate first seeks informal resolution of his claim by consulting prison personnel. §If this informal effort fails, the prisoner 'may file a formal written complaint on the appropriate form, within 15 calendar days of the date on which the basis of the complaint occurred.' Should the warden fail to respond to the inmate's satisfaction within 15 days, the inmate has 20 days to appeal to the Bureau's Regional Director, who has 30 days to respond. If the inmate still remains unsatisfied, he has 30 days to make a final appeal to the Bureau's General Counsel, who has another 30 days to respond. If the inmate can demonstrate a 'valid reason for delay,' he 'shall be allowed' an extension of any of these time periods for filing. P filed a pro se complaint against four prison employees: the hospital administrator, the chief psychologist, another psychologist, and a physician (Ds). P alleged that Ds had violated his constitutional rights under the Eighth Amendment by their deliberate indifference to his needs and medical condition resulting from a back operation and a history of psychiatric problems. The District Court dismissed because P had failed to exhaust prison administrative remedies. The Appeals Court affirmed. The Supreme Court granted certiorari.