This volume contains the first translation from German into English of the extant correspondence between Leo Strauss and Gerhard Krüger. The translation by Jerome Veith, Anna Schmidt, and Susan M. Shell is clear, accurate, and a pleasure to read. It comes with an introduction that puts the correspondence in historical context and seven interpretive essays. Also included are explanatory notes and a translation of Krüger's 1931 review of Strauss's first book, Spinoza's Critique of Religion. Finally, the reader will find here a translation of Strauss's 1964 German preface to his The Political Philosophy of Hobbes, where he famously declares that since the publication of the Spinoza book in 1930, “the theological-political problem has remained the theme of my investigations” (228).

When the editor of Leo Strauss's Gesammelte Schriften (GS), Heinrich Meier, published the Strauss-Krüger correspondence in 2001, it attracted little attention in the English-speaking world. Yet this correspondence is of exceptional philosophic interest, not least for scholars who wish to study the “change of orientation” that Strauss, by his own admission, underwent during the 1930s. For almost all the letters included in this volume date back to the important period between 1930 and 1935. (The correspondence between the two men, interrupted by World War II and other events, was not to be resumed afterwards as Krüger suffered a series of incapacitating strokes in the early 1950s.) According to Strauss's autobiographical account in the 1964 preface, it was a shared philosophic interest in theology that linked him to Krüger (228). Indeed, among his friends at the time, Krüger was the one most interested in the problem of the relation between revelation and philosophy and the one most versed in theology. Moreover, as one contributor to the volume, Daniel Tanguay, observes, Krüger was “the only Christian believer with whom Strauss seriously engaged in discussion” (128). For this reason alone, the Strauss-Krüger correspondence fully deserves the attention it receives here. It is also worth noting that Strauss's seminal work on Hobbes was influenced by, and in part a reply to, Krüger's interpretation of Descartes in an important 1933 essay (see, e.g., 68, 74; GS 3:494, 496).

That the theme of theology lies at the heart of the epistolary exchange between Strauss and Krüger is not contradicted by the fact that Enlightenment philosophy, and modern philosophy in general, are the main focus of their most important letters. For both men sought to understand what they viewed as the inadequacy of the Enlightenment's critique of the Bible and of revealed religion. And both sought to grasp the spiritual and intellectual crisis that they thought had been caused by that inadequacy. Strauss, for one, expressed his thesis about the crisis of modernity through a metaphor: what the Enlightenment and its philosophic aftermath had brought into existence was not the kingdom of reason it had intended to create, but the so-called second cave—“the cave beneath the cave.” Strauss's correspondence with Krüger contains the most extensive discussion anywhere of this memorable if somewhat enigmatic metaphor (inspired by the Republic of Plato). In an excellent and informative essay, Daniel Tanguay offers an interpretation of what Strauss means by the “second cave” (chap. 5). Tanguay's analysis is penetrating and balanced, though not every reader will be persuaded by his conclusion that the problem of the “second cave,” for Strauss, is not the problem of historicism or historical relativism (cf. 48, 52). Rather, according to Tanguay, Strauss equates the second cave with revealed religion as such.

Krüger initially seemed to accept Strauss's thesis that the Enlightenment had produced a “second cave.” He certainly shared Strauss's view that modernity was in a state of spiritual and intellectual crisis, and he, too, eventually sought a solution in premodern times. He rejected, however, Strauss's suggestion that the modern crisis might be overcome through a comprehensive recovery of classical philosophy. In his judgment, such a recovery was ultimately neither desirable nor possible for the simple reason that the spirit of mankind had been transformed by the coming of Christ. Modern man was no longer the being analyzed by the ancient philosophers. Indeed, the coming of Christ marked the turning point of human history even from a philosophic point of view, for “Christ's factual dominion [Herrschaft] over the spirit of post-ancient humanity,” which admittedly had become indirect in modern times, was the “substantive [sachlich] and historical core” of historicism (45). The path out of the modern crisis lay, for Krüger, not in a recovery of classical philosophy but in a “hopeful knowledge” reminiscent of the Christian Platonism of St. Augustine (cf. letter 37).

Strauss agreed with Krüger that the spirit of mankind had been profoundly transformed by Christianity, though he denied that the transformation was permanent or inescapable (e.g., GS 3:666–67). He rejected the claim of post-Christian philosophy, notably of Heidegger, to have preserved certain “truths” brought to light by the Christian religion that were unknown or insufficiently known to the ancients (e.g., the historicity of man), even though Christianity was held by the same post-Christian philosophy to be “false” as a religion. More than once, Strauss suggests that there exists “a simply a-Christian philosophy” whose primary concern is the discovery of the measure or standard (Maßstab) by which human life is to be judged (48, 53). This philosophy—the philosophy of Plato and Aristotle—seeks to uncover “the order of human things” or “the right order of human life,” a theme neglected by modern philosophers such as Hobbes. These philosophers assumed that the measure in question was already known and focused instead on achieving a universal application of it (e.g. 38–39, 42–43, 48–51, 53, 70). Moreover, the quest for knowledge of the Maßstab points to the question of law (nomos), for the right order of human life comes to sight—to begin with—as the order of the duties defined by the law of the city. Thomas Pangle (chap. 3) focuses on this general aspect of the correspondence. He explores what light the epistolary exchange between Strauss and Krüger sheds on the reorientation undergone by the former in the 1930s, arguing that Strauss's key insight in those years was the realization that political philosophy was decisively important for Plato. Indeed, under the guidance of Maimonides and Farabi, Strauss came to understand that Platonic political philosophy is the means of addressing the theological question. And at the center of Platonic political philosophy lies the analysis of law. Strauss's correspondence with Jacob Klein in the years 1937–1939, in particular, testifies to his deep and early interest in the Laws.

The volume highlights the role (or lack thereof) played by Kant in the respective returns of Strauss and Krüger to Plato. I must limit myself here to a single essay. Susan Shell (chap. 7) zeroes in on a persistent puzzle—“the absence in any of [Strauss's] published writings of a thematic treatment of Immanuel Kant” (165). She suggests that Strauss showed an appreciation for Kant that may have provided the motif for his early studies of Spinoza and Hobbes, but that he probably regarded Kant's philosophy in the end as “theoretically speaking a dead-end” (173). For Kant had endeavored to limit knowledge in order to make room for faith. He had tried to render religion immune to scientific criticism by placing science and religion on parallel but separate planes. As a result, a genuine confrontation between science and religion, between belief and unbelief, had become impossible. But a confrontation between them cannot be avoided, according to Strauss. Philosophy and revelation cannot be assigned separate spheres or planes because they both make assertion intended to be true assertions about the same subject: the world and human life (cf. 174). Despite this fundamental defect, the philosophy of Kant could nevertheless be said to point to the plane on which, according to Strauss, philosophy and revelation could engage each other fruitfully: the plane of the (moral) law.