Training our attention to the production and circulation of philosophical manuscripts across the seventeenth and eighteenth centuries, Clandestine Philosophy: New Studies on Subversive Manuscripts in Early Modern Europe, 1620–1823 is a very valuable resource, complementing recent studies of the early Enlightenment as well as political and philosophical radicalism in the period. Editors Gianni Paganini, Margaret C. Jacob, and John Christian Laursen curate this series of erudite essays that foreground anonymous or lesser-known manuscripts, works that are often neglected by early modernists—Jean Bodin's Colloquium Heptoplomeres, the anonymous Theophrastus Redivivus, the anonymous Traité des trois imposteurs, Hadriaan Beverland's De Prostibulis Veterum, and John Toland's Pantheisticon, among many others—that offer alternatives to the academic and/or systematic philosophy of the period, especially as they move across regional borders and languages in unexpected ways.

Several contributors (notably, Paganini, Laursen, and Winfried Schröder) detail the current state of the field—that is, the study of early modern clandestine texts—and direct readers to relevant studies, editions, and bibliographies. So too do these scholars expend considerable effort outlining what makes a text radical or subversive. They do not set prescriptive terms themselves but rather explore how the subversive content of a given manuscript is inextricable from its clandestine status. Instead, as Susan Seguin shows in a brilliant study of how clandestine texts circulated among the members of the Académie Royale des Sciences, unorthodox texts bore influence at the margins of the major institutions of the period. Such clandestine manuscripts—most handwritten, some printed but limited to private circulation—were integral to intellectual life in early modernity, offering philosophical reflection in genres and modes that would have faced stricter censorship in more public milieux such as the book trade. Indeed, as Antony McKenna and Fabienne Vial-Bonacci reveal in their study of the Amsterdam printer Marc-Michel Rey, writers, readers, and booksellers alike saw the traffic in clandestine materials as distinct from the official over-the-counter business. The essays in this volume do much to flesh out our understanding of this distinction.

Many of the contributors foreground a text or texts that are foreign or marginal to the usual accounts of early modern philosophy. Indeed, in his crucial contribution Jeffrey D. Burson illustrates the degree to which these heterodox texts are eclectic, often contradictory, more haphazard than either the academic philosophy or the emergent rationalism with which early modernists are more familiar. Paganini demonstrates, for instance, how the author of Theophrastus Redivivus discovers religion as a matter of power rather than faith or piety, promoting an atheistic approach to nature and civil society. But Theophrastus Redivivus is remarkably different from comparable contemporary works like Hobbes's Leviathan or Spinoza's Ethics, to say nothing of the canonical texts of the Enlightenment in the eighteenth century; Theophrastus Redivivus is a far less systematic work, the product of many influences, bearing much more relation to Renaissance naturalism than to any of the major movements in the history of philosophy as we know it. Nevertheless, the author of Theophrastus Redivivus offers a rich account of nature and history absent God's providence, at odds with the dominant intellectual currents and institutions of the seventeenth century. Clandestine manuscripts like this show how writers and readers alike tarried with unorthodox ideas without taking direct recourse to systematic philosophy.

We learn, instead, how diverse readers encountered heterodox ideas across other genres of philosophical writing, from biblical exegesis to joke books to pornography to speculative anthropology. The essays are focused, detailed, and full of insight: Wiep van Bunge and Rienk Vermij turn our attention to heterodox ideas in the Dutch Republic, foregrounding the circulation of Socinian and libertine manuscripts, respectively, in the seventeenth and early eighteenth centuries. Martin Mulsow explores the exchange of heterodox ideas in early eighteenth-century Germany by way of biblical philology, foregrounding a text that posits Joseph as Christ's natural father: a discovery that upsets orthodox approaches to the Trinity and Christ's offices. Frederik Stjernfelt introduces Danish mathematician Christiffer Dybvad and his anticlerical jest book. Inger Leemans offers a comprehensive survey of clandestine writing on sex and sexuality during the period, including anatomy and pornography; Karen Hollewand, in turn, foregrounds Beverland's writing on sexual liberty and libido. Whitney Mannies attends to Toland's heterodox philology, rich in philosophical detail and critical potential; John Marshall delivers a study of the Treatise of the Three Impostors, an infamous work that exposes religion tout court as a political endeavor, faith as an expression of obedience.

In the final two essays, Jonathan Israel and Laursen shift the attention from Northern Europe of the seventeenth and eighteenth centuries to Spain during the revolution of 1820–23, underscoring the abiding importance of early modern clandestine philosophy in its diverse modes. Such texts, they show, are too often occluded in familiar accounts of Enlightenment and its origins. Israel and Laursen, together with the other contributors to this excellent volume, make a compelling case for the importance of seventeenth-century clandestine philosophy and its enduring influence on the history of radical philosophy at large.