The concept of a sociomoral milieu has become a central analytical tool for historians of Catholicism and of religion more generally in modern Germany. Understood as coherent, interconnected ideas, practices, and institutions instilling a strong sense of group solidarity, in the case of Catholics generally under clerical control, the creation of such a milieu has been perceived as central to the ability of the Catholic Church to meet the challenges of deeply unsettling political and constitutional changes and rapid social and economic transformation, retaining or even increasing the loyalty of the lay faithful through the 1960s. Jeffrey Zalar's study of popular reading practices among German Catholics during the long nineteenth century is a vigorously written attack on the milieu concept. Its adherents, he asserts, misunderstand the theological imperatives motivating the actions of the clergy and vastly exaggerate their extent and effectiveness. Deploying an impressive body of empirical evidence from extensive research in diocesan archives and a careful reading of religious periodicals, Zalar makes a strong case for his critique. Not all elements of the interpretation of his empirical findings, though, are entirely convincing.

A regional study of Rhineland-Westphalia, one of Central Europe's Catholic heartlands, the book is divided into two parts, covering roughly the periods 1770–1880 and 1880–1914. Zalar begins with a discussion of enlightened intellectuals who promoted an ideal of reading carefully selected texts for self-cultivation and intellectual improvement, rejecting indiscriminate reading and reading for pleasure as problematic practices of the poorly educated. Such thinkers had a particularly poor opinion of Germany's Catholics. The argument was that Catholics, mired in ignorance, kept in tutelage by an authoritarian clerical hierarchy, were particularly in need of proper reading material. Political changes of the era, the incorporation of the Rhineland into revolutionary and Napoleonic France, and then the onset of Prussian rule in western Germany after 1814, facilitated the implementation of the Enlightenment reading program.

These developments were severe blows to the Catholic theology of reading, characterized by a preference for the clergy reading out loud to the faithful, exclusively reading church-approved literature, and reading for the inculcation of doctrinally proper morality and piety. This theology had certain similarities to Enlightenment ideals because both condemned indiscriminate reading and reading for pleasure. As the author reluctantly admits, two competing elites vied to regulate behavior of the lower and middle classes, although he perceives the enlightened as motivated by anti-Catholic bigotry, and the church as wishing to keep the faithful far from the snares of Satan.

Zalar's explication of Catholic theology is peculiar, employing passages from Dante's Inferno and The Lord of the Rings, and from Homer's Odyssey as interpreted by the Jewish neo-conservative Leon Kass. Ironically, Zalar's own account accepts enlightened characterization of Catholic theology as authoritarian and monolithic. What he describes seems closer to positions of neo-orthodox or ultramontanist, later integralist theologians. Differing attitudes of enlightened, Hermesian, or modernist Catholics are, in this part of the book, ignored.

When it comes to the actual practices of lay Catholics, Zalar presents a picture of unstructured reading covering, certainly, Catholic devotional texts, but also Protestant Bibles and pamphlets, or enlightened literature, particularly in the form of almanacs and calendars, as well as adventure stories and romance novels. This state of affairs remained constant throughout the period. The many organizations and practices of Catholic renewal that spread in Central Europe from the 1840s onward, including the Borromoäusverein (St. Charles Borromeo Association) for the promulgation of devout literature, had, in Zalar's account, no particular effect.

Conditions changed in the years between 1880 and World War I. Increasing urbanization and industrialization and the growth of mass entertainment were still more diversions from theologically approved reading. Lay Catholics themselves, taking up liberal, Protestant, and enlightened ideals (the author's conflation of these three, a replication of nineteenth-century Catholic polemics, is an annoying feature of his argument) dominant in Prussia, wanted to read more widely for occupational advancement and intellectual self-improvement. They asked the bishops for exemption from the prohibitions of the Index of Forbidden Books, or simply read prohibited works without permission.

At the same time, the end of the 1870s anti-Catholic Kulturkampf (because the author does not use state archives, his account of Wilhelmine-era government policy is less clear) made possible new initiatives by the clergy, lay activists, and the politicians of the Center Party, such as the Volksverein für das katholische Deutschland (People's Association for a Catholic Germany) or the Christian trade unions and peasant leagues. Supported by the Volksverein, a new leadership of the Borromäusverein launched a vigorous campaign of organizational and intellectual renewal. Membership grew and finances improved. The group's lending libraries were overhauled, expanded, and made easier to use, so circulation increased substantially. Zalar emphasizes the role of bookish young women in these developments. Besides pious texts, the libraries featured popular and literary fiction, as well as professional literature and nonfiction writings on science, technology, geography, and a host of other topics. If these books were not all written by Catholic authors, they were at least vetted to ensure that their content did not blatantly contradict church teachings.

Zalar presents these features of the pre-1914 era as part of his declension narrative, an example of the ever more evident failure of the theological program of pious reading. The church's concession to the demands of the laity for godless texts would ultimately culminate in the abolition of the Index of Forbidden Books at the Second Vatican Council. The author's regret for this decision concludes his work. It is unclear why Zalar interprets the addition to libraries of the Borromäusverein of books by devout writers such as Clemens Brentano or Annette von Droste-Hülshoff as examples of the decline of Catholic piety. Zalar does, in this part of his book, admit that there was a theological current, known around 1900 as modernism, whose own reading program corresponded to the new developments. Here too he tends to present Catholic theology as monolithic, mentioning opposition to the new directions of church-sponsored reading without putting it in the context of the sharp clash between integralists and modernists, which was a central feature of Catholicism in the early twentieth century.

One could just as easily interpret these initiatives as examples of a flexible and successful response of the Catholic milieu to changed conditions and attitudes. The laity, after all, continued attending mass and voting for candidates of the Center Party and the Christian Democratic Union (CDU) in large numbers until the last third of the twentieth century. As one example of the pervasiveness of lay rejection of Catholic reading theology, Zalar mentions the 1910 request of a secondary school teacher from Neuss to read works on the Index of Forbidden Books so she could prepare for the principal's exam. The teacher was Christine Teusch, who would go on to be a leading Catholic politician, sitting for the Center in the Weimar National Assembly and then for the CDU in the Federal Republic's constitutional convention, was during the Nazi era a member of the clandestine Catholic anti-Nazi Kölner Kreis (Cologne Circle) and the first woman to be a government minister in the Federal Republic. Her life suggests a different interpretation of the relationship between reading and rebellion and of the nature of the Catholic milieu than the one propounded in this book.