Dennis Rasmussen's original, well-researched, convincing book tells the story of the friendship between David Hume and Adam Smith from their first meeting in 1749 until Hume's death in 1776. The book also considers these two authors’ lives before their encounter and examines Hume's legacy in Smith's life. In this respect Rasmussen offers a detailed analysis of Smith's Letter to Strahan (1776), published shortly after Hume's death, and of its reception by contemporaries. This letter by Smith, which ‘was an attempt to vindicate Hume's reputation and secure his legacy in a world that was frequently hostile to him and almost always hostile to his ideas’ (p. 222), is also contained in the appendix to this volume, along with Hume's posthumous autobiography. However, this book is more than merely an intellectual biography of the two major representatives of the Scottish Enlightenment, whose lives intertwined over a period of almost three decades. Throughout this volume Rasmussen elucidates the reciprocal influences between Hume and Smith, which emerge not only from their correspondence with each other and with (relatively few) other intellectuals, but also from their manuscripts and published works. Therefore, this book can well be considered as a comparative study of these two thinkers’ philosophical, moral, political, economic and religious views in the context of the ‘intellectual golden age’ of Scotland. Besides concentrating on Hume's and Smith's letters and writings, Rasmussen indeed pays great attention to these two philosophers’ interactions with the cultural environment of the Scottish Enlightenment. Moreover, he takes into account their reactions to the major political and religious events of the day and the impact that such events had on their ideas.

One of the main objectives of this book is to refute several purported dichotomies between Hume and Smith – dichotomies that are widely accepted, although based on ill-grounded assumptions and superficial readings of these two authors’ works, as Rasmussen brilliantly demonstrates. Contra the view that ‘Hume was a philosopher interested primarily in abstract metaphysical and epistemological questions, while Smith was a hardheaded economist focused on more practical matters’ (p. 12), Rasmussen calls attention to both authors’ interests and competencies in a number of fields. In fact, political economy was only one of the intellectual interests that Smith pursued, along with ethics, law, rhetoric and several other sciences, whereas Hume was a much more practical man than is commonly believed. For instance, Smith's own theory of moral sentiments shows several improvements on Hume's, while Hume's original arguments in support of free trade predate Smith's masterpiece, An inquiry into the nature and causes of the wealth of nations (1776). Moreover, Rasmussen persuasively argues that it is incorrect to distinguish between a ‘conservative’ Hume and a ‘liberal’ Smith. Actually, both of them supported the liberal, commercial order of their time, while both opposed sudden, large and often unneeded innovations in politics. Finally, Rasmussen tackles the widespread view that Smith was a believing Christian, whereas Hume was a sceptic with regard to religion or, perhaps, even an atheist – and this is why he was labeled an ‘infidel’ in his time. Chapter x of this book, ‘Dialoguing about natural religion’, particularly focuses on the two philosophers’ views on religion. In this regard Rasmussen observes that Hume, far from overtly expressing atheistic views, limited himself to disproving all forms of natural religion and exposing the pernicious effects of positive religion. Rasmussen therefore concludes that Hume was, most probably, simply an agnostic in theological matters. This claim, which I consider correct, is largely based on an accurate analysis of Hume's Dialogues concerning natural religion (1779). I would only like to add that Rasmussen's conclusion would have significantly benefitted from a closer consideration of other works by Hume, such as An enquiry concerning human understanding (1748), especially section 10, ‘Of miracles’, and book i of A treatise of human nature (1739–40), which delineates the scope and limits of human understanding. Concerning Smith, Rasmussen argues that, although the author of The wealth of nations was much more reticent than was Hume on religious subjects, he was almost certainly not a believing Christian. He was, instead, ‘a sceptical deist’, by which Rasmussen means that Smith probably believed in a distant, benevolent higher power, but he was suspicious of all forms of religious devotion.

In conclusion, Rasmussen's comparative study of Hume's and Smith's views on knowledge, morality, politics, economy and religion effectively reassesses the reciprocal influences between these two philosophers and thus contributes a fresh understanding of how their interaction helped to shape modern thought. This original, elegantly written, compelling essay, which combines textual analysis with a contextual approach, is likely to have a momentous impact on the historiography of the Scottish Enlightenment and of the Age of Enlightenment as a whole.