This is an excellent study of the literary career of Paul-Henri Thiry the Baron d'Holbach (1723–1789), the atheistic philosophe of German background, and an important landmark in contemporary Enlightenment research. It is also an event in research into the changes in religious apologetics in the late eighteenth century. This study's importance derives both from its intrinsic value but also from the unaccountable fact that d'Holbach, its main focus, has been neglected by Enlightenment scholars at all stages despite the historical impact of his publications. This neglect was due in part, Curran explains, to the lack of sources of biographical information about d'Holbach's life and activities. But it is equally due to the pervasive, strange, and unjust myth that grew up in the nineteenth century and prevailed through the twentieth that d'Holbach is a dull and uninteresting author, a judgment that appears exceedingly odd to anyone familiar with his extremely subversive religious, philosophical, social, and political views. In any case, his Système de la nature (1770), in particular, administered a tremendous shock within the world of late Enlightenment European intellectual culture and provoked a powerful and lasting reaction from both Catholic and Protestant theologians and moderate enlighteners which forms a significant chapter in church history.

Curran begins by following Jeremy Popkin, Daniel Gordon, Elisabeth Eisenstein, David Bell, and Jonathan Israel in pointing out, quite correctly, that while Robert Darnton's historical researches revealed d'Holbach to have been the hand behind eight of the “ten most popular pre-Revolutionary clandestine anti-religious treatise” that appeared in France (5), and that he was one of the most widely read Enlightenment authors, neither Darnton nor anyone else has thus far seen fit to write about d'Holbach as the pre-eminent figure that he undoubtedly was. Curran advances considerably beyond the point reached by the older scholarship devoted to d'Holbach, in particular the works of W. H.Wckwar and Pierre Naville, by drawing on the substantial material and fresh information from the numerous books, brochures, and articles, the 128 recorded publications, published in the 1770s and 1780s, responding to the challenge offered by d'Holbach's major works. Churchmen and moderate enlighteners eager to defend religion regarded his books as especially dangerous. They did so less for his detailed partially scientific exposition of materialist doctrines as such, a dimension of d'Holbach's original work largely confined to the Système de la nature, than to his readiness to deduce moral, social, and political conclusions from his atheism and materialism, something he does, both in that work and still more in La Politique naturelle (1773) the Système social (1773) and La Morale universelle (1776). D'Holbach emerged as a social critic in a notably more systematic and challenging manner than either La Mettrie or Diderot.

As Curran notes d'Holbach remained high-profile, especially in Catholic and Protestant apologetic literature, through the 1770s and 1780s down to 1789 and not the least valuable feature of this slim volume are two appendices, one extremely useful eighteen-page list of the books published partly or wholly responding to d'Holbach (appendix 2), and another ten-page list of the articles responding to the challenge that appeared in the periodical press (appendix 3). The only critical note I would sound in my otherwise very positive reaction to the scholarly research amassed here, is that Curran hardly says anything about the considerable role d'Holbach's authorship, personality, or publications played in the French Revolution. From 1789 onward, he began to be more widely proclaimed as the author of his books and the political role of his publications, though realized earlier, took on a fresh and expanded significance, none of which is discussed or mentioned here.

The freshest and most important aspect of Curran's book is certainly his fascinating analysis of the Europe-wide intellectual response to d'Holbach. Curran demonstrates that the controversy over d'Holbach's books transformed the character of Christian apologetics. He did so not just by shifting the main focus away from deism and anti-clerical pleas for a wide toleration to atheism and materialism, but also by forcing Christian writers to discard some of their earlier hostility toward criticism of religious authority and intolerance and to accept a more accommodating approach, even to Voltaire, realizing this was the price that had to be paid if the churches were to respond effectively to the materialist challenge. Thus, the leading Swiss Protestant naturalist, Albrecht von Haller (1708–1777), who had earlier attacked Voltaire as a virtual Spinozist and materialist in a text of 1760 and supported the royal suppression of the Encyclopédie, applauded Voltaire for his Dieu, Réponse de Mr de Voltaire au Système de la nature (1770). Voltaire attacked atheism, insisting on belief in God and divine providence and the need of the majority of society to remain under ecclesiastical supervision. In the 1770s and 1780s, this sufficed to modify earlier hostility toward him considerably. Thus, Nicolas-Sylvestre Bergier (1715–1790), the most formidable and effective Catholic ecclesiastical writer to answer d'Holbach, similarly shifted his sights for the remainder of his career as a leading Christian apologist from deism, and Voltairean anti-clericalism, to attacking atheism and materialism as a social and moral as well as metaphysical danger.

Bergier answered d'Holbach not by citing scripture or ecclesiastical authority, but by retaliating using the tools of philosophy and science. In the wider context of Enlightenment historiography, Curran's book deserves to be especially cited for its efforts to bring a large proportion of late eighteenth-century Christian apologetics into the sphere of the (moderate) Enlightenment and correct the excessively crude image of so-called anti-philosophes as propagators of Counter-Enlightenment. In this context he pertinently criticizes D. M. McMahon's Enemies of the Enlightenment (2001) which performed a good service by drawing attention to a large group of Catholic polemicists who had been unjustly neglected but at the same time was profoundly mistaken and deeply unhelpful in designating this group of writers adherents of the Counter-Enlightenment. Bergier, Lamourette, and many if not most of these writers decidedly more properly belong within the mainstream ranks of the (moderate) Enlightenment.