This small book deals with a subject that has not just been neglected but whose very existence has been generally ignored or denied. The author, who is known as an able and sympathetic historian of early modern Roman Catholic monasticism, tells us that he was shocked when he first learned of the very existence of monastic prisons and, still more, when he found out what took place in some of them, but felt it to be his duty as a historian to investigate and report on them even though they sully the image of monasticism. The result is a revelatory book, describing the phenomena of monastic prisons and torture chambers, confuting those apologists who have denied these facts but explaining why in many orders brutal punishment was deemed indispensable.

Early modern society, of course, assumed that not only prisons but also harsh punishments and torture were essential to the maintenance of law and order. Those who were received into monasteries were in general removed from society's ordinary system of justice, but entering a religious order did not necessarily prevent a person from becoming a thief, a disturber of the peace or a sexual predator, or even a murderer; and keeping monks and nuns under control was in general left by the state to their monasteries. Many orders or individual houses were ready to discipline their inmates with a severity almost equal to that of secular justice. Torture was common, and there were cases of inmates being starved or beaten to death. The principal exception was that it was unusual, but certainly not unknown, for a monastic court to prescribe and inflict the death penalty.

Study of the subject is rendered especially difficult because monasteries did not have to keep records of crimes and punishments in the way that secular authorities did, and moreover by the later eighteenth century monastic leaders in more civilised areas had become sensitive to the public discredit that revealing information about monastic discipline might bring. Ulrich finds a number of instances of downright lies about such matters uttered by abbots and other monastic authorities.

This is a very short book, but it is packed with information that is mostly quite unknown to general and even to monastic historians – for example, as to which orders' monasteries regularly had prisons and which (especially the Benedictines) did not. It seems that the Franciscans were especially severe on friars whom they considered delinquent. Few books of much greater length than this one cast so much new light on their subject.