The term ‘Radical Enlightenment’ denotes a section of Enlightenment culture consisting of authors and currents that adopted deism, pantheism, atheism or materialism and rejected providence, miracles and revelation in religious matters, while advocating republican, egalitarian and fundamentally democratic political ideas – thus opposing the divine right system of power. This term was used well before the twentieth century, but it first obtained its current semantics in the work of Leo Strauss. More recently, the concept of ‘Radical Enlightenment’ has played an important role in historiography, particularly regarding the relationship of the Radical Enlightenment to the Moderate Enlightenment (which attempted to combine rationality with religious tradition and the political status quo), its contributions to the Age of Revolutions, and its significance in the development of modern secular societies. Starting in the 1970s, virtually all students of the philosophical, scientific and political thought of the Enlightenment have paid attention to the Radical Enlightenment. Nevertheless, Reassessing the Radical Enlightenment is the first collection of essays specifically devoted to clarifying this concept.

In the first part of this book, Jonathan Israel and Margaret Jacob explain their respective notions of ‘Radical Enlightenment’. Israel argues that ‘eliminating miracles, Revelation and divine providence, and proclaiming scientific and philosophical “reason” the exclusive criterion for determining truth, this wing of the Enlightenment sought to reconceive and reorganize the entire moral and political order’ (p. 15). And, although defeated in the nineteenth century, the Radical Enlightenment succeeded (at least in part) in the long run. While avoiding focus on the long-term effects of the Radical Enlightenment and attaching more importance than Israel does to English influences, Jacob too views the Radical Enlightenment as characterised by ‘a commitment to republicanism, a turn toward materialism or atheism, and a search for a purely naturalist form of religious behaviour’ (p. 48). All in all, Israel's and Jacob's chapters highlight the points of agreement, rather than the differences, between their influential accounts of the Radical Enlightenment. The first part of the book also presents a thought-provoking essay by Harvey Chisick, who concentrates on the question whether materialist metaphysics necessarily led to egalitarianism, republicanism and democracy, reconsiders Enlightenment views on race and slavery, and revalues the impact of the Radical Enlightenment on the French Revolution. Finally, Frederik Stjernfelt offers us a detailed, exhaustive and very helpful history of the term ‘Radical Enlightenment’ and of its various connotations in historiography.

Part ii of the book comprises five chapters which reassess the importance of some key figures and aspects of the Radical Enlightenment, especially in its origins and early developments. Whereas Nancy Levene argues that Spinoza's radicalism emerged not only in his criticism of religion, but also in his rethinking of nature, Beth Lord denies the existence of ‘a connection between substance monism and egalitarianism, or between human nature and equality’ (p. 128) in Spinoza's thought: Lord contends that, to Spinoza, moral equality was a ‘fiction of the imagination’ connected to democratic citizenship. Although different in their topics, approaches and conclusions, Levene's and Lord's chapters are stimulating and valuable in that they raise new issues for debate. Spinozism is also the subject of Ian Leask's essay, which brilliantly delineates the Spinozist character of John Toland's biblical hermeneutics and historical-political considerations in Origines Judaicae (1709). The remaining two chapters in part ii are devoted to less known but not less interesting topics. Charles Devellennes sheds new light on the atheism and radical republicanism of the French Catholic priest Jean Meslier, highlighting Bayle's influence on Meslier's thought. Finally, Wiep van Bunge explores the waning of the Radical Enlightenment in the Dutch Republic in the early eighteenth century, which was due to the mitigation of theological tensions and to the spread of Newtonian natural philosophy.

The third and last part of this volume deals with the Radical Enlightenment in Europe and the New World after about 1720. Some of the essays in part iii, focusing on specific authors and contexts, invite reflection on the distinction between ‘Radical’ and ‘Moderate’ Enlightenment: Eric Palmer's chapter shows that many eighteenth-century French clergymen were involved in inquiries into libertinism and atheism; Falk Wunderlich calls attention to the work of the Göttingen scholars Christoph Meiners and Michael Hißmann, who were both Christian and materialist; and Winfried Schröder points out the contradictions of de Sade's work, which, although endorsing materialism and atheism, differed from the Radical Enlightenment in that de Sade's controversial views could find no rational justification. The remaining three chapters in part iii reconsider the role of the Radical Enlightenment in the growth of political and gender equality: Ultán Gillen investigates the influence of Radical Enlightenment and revolutionary discourses on the political upheaval in late eighteenth-century Ireland; Devin Vartija points to the importance of empathy in the development of Enlightenment political egalitarianism; finally, Jennifer Davis reassesses the part that the transnational movement for educational egalitarianism played in promoting gender equality in Europe and the Americas.

Although this book is far from being comprehensive and does not claim to have the ‘final word’ on this subject, as Ducheyne acknowledges in his concise but illuminating introduction, it effectively accomplishes its two-fold task: ‘first, to provisionally provide a (partial) synthesis of the state of the art and, second, to push forward research on the Radical Enlightenment’ (p. 2). The chapters that concentrate on the history of this concept and on the ongoing debate on the subject, along with the essays that reconsider the historical significance of Spinoza and other important figures of the Radical Enlightenment, are very useful to both experienced scholars and newcomers to the field. Moreover, the chapters that examine some of the least studied aspects of the Radical Enlightenment open up new possibilities for research on this topic. This highly-readable, intelligently assembled collection of essays represents a significant, original, inspiring contribution to the study of the Enlightenment. This volume is indeed likely to become a standard book for all those interested in the Radical Enlightenment.