This volume concentrates on the changes in religious thought and institutions in the eleventh and twelfth centuries, and includes not only monks and nuns but also less organised types of life such as hermits, recluses, crusaders, and penitents. It is complimentary to Professor Constable's subsequent book, The Reformation of the Twelfth Century (now also published as a paperback), but is dissimilar to it in examining three themes over a long period, from late Antiquity to the seventeenth century, in order to show how they changed over time.