These three volumes form a major reference work covering six hundred years of monastic history. The volumes comprise fully documented, critical lists of monastic superiors from the tenth century reform to the dissolution of the monastic houses ending in 1540. Record sources have been provided by surviving monastic archives, episcopal and papal registers, governmental enrolments and archives, court records, private, family and estate collections. Full references are given for establishing the dates and outline of the career of each abbot or prior, abbess or prioress, when known. The lists are arranged by order: the Benedictine houses (independent; dependencies; and alien priories); the Cluniacs; the Grandmontines; the Cistercians; the Carthusians; the Augustinian canons; the Premonstratensians; the Gilbertine order; the Trinitarian houses; the Bonhommes; and the nuns. The volumes provide an essential foundation for all prosopographical study of the religious history of the period and are a fundamental tool of medieval research.