This is an important intervention in current scholarly debates about the nature of early modern Western European alchemical thought and practice. Specifically, it provides a timely counterweight to the now dominant arguments of William Newman and Lawrence Principe known as the ‘New Historiography of Alchemy’ (4). For rather than envisaging alchemy as merely an esoteric discipline which concealed its secrets from the profane multitude by draping them in a veil of recondite tropes and abstruse allegories, let alone—in the vein of Ben Jonson’s comedy The Alchemist—as fraud perpetrated on the gullible, their research has emphasised the place of alchemy within the history of science. In particular, Newman and Principe have shown that before the late seventeenth century the boundaries of what we retrospectively call alchemy and chemistry were not solidly fixed but rather extremely diffuse. This privileging of laboratory alchemy, however, has come at a cost, namely the marginalisation of what since the nineteenth century has been called spiritual alchemy. Although this anachronistic term seemingly defies classification, Zuber defines it as the “practical pursuit of inward but real bodily transformation” (9). As such, the notorious alchemical obsession of transmuting base metals into gold and the concomitant search for the Philosopher’s Stone or divine elixir—the agency through which this transformative process would be effected—becomes explicable, at least for certain figures, as a quest for spiritual rebirth that was accompanied by “actual bodily changes” (11). Moreover, as Zuber’s subtitle indicates, the Görlitz theosopher Jacob Boehme (c.1575–1624) plays an important role in this rigorous and serious examination of the “religious aspects” of alchemy (6). Indeed, rather than attempting a comprehensive overview of the development of spiritual alchemy in both Protestant and Catholic circles, Zuber has instead provided a narrower focus: essentially, the antecedents of this aspect of Boehme’s thought, its expression in his writings, followed by an exploration of various creative adoptions and adaptations within an interlinked reception history that was “shared, transmitted, or semi-independently rediscovered” (12). Spiritual Alchemy’s ambitious chronological scope therefore extends from the sixteenth century Radical Reformation to the early twentieth century.

Chapter one focusses primarily on Paracelsian networks and pseudo-Weigelian alchemy; that is pseudepigraphal texts written under the name of the Spiritual Reformer Valentin Weigel (1533–1588). In particular, Zuber discusses the cryptic Azoth and Fire (mid-1580s to 1599) and the more accessible Concerning the Dialogue on Death (published in 1614). At the core of the former, in Zuber’s opinion, was the “mystical identification with Christ” which would enable the “transmutation of man into a heavenly state” (24). The latter intriguingly mentions antimony several times and a printed version may have come to Boehme’s attention (29). One alchemical work that Boehme certainly referenced was Wasserstein der Weysen [Water-Stone of the Wise] (published 1619), very likely by Johann Siebmacher of Nuremberg. This treatise, which had been composed in 1607, was a less radical restatement and expansion of the “basic points of pseudo-Weigelian alchemy” (35). Another early reader and propagator of pseudo-Weigelian alchemy was Paul Nagel (d.1624), an astrologer and chiliastic prophet from Torgau, Saxony whose social network overlapped with Boehme’s to a significant degree. Given this linkage, Zuber understandably spends some time in his second chapter examining both Nagel’s Aurum divinum 666. centenariorum [Divine Gold of the 666 Hundredweights] (1618) and Nagel’s Leo rugiens (1620), which he calls a “rambling work” packed with “numerological, astrological, and apocalyptic speculations” (43).

In the third chapter Zuber turns to Boehme’s own spiritual alchemy of rebirth. Beginning with the celebrated ‘Aurora’ (incomplete, 1612) especially its 22nd chapter in which Boehme outlined seven stages in the purification of gold, Zuber shows how Boehme’s initial unfamiliarity with alchemy developed into a more mature understanding of this “philosophical work”, particularly as expounded in his near impenetrable ‘Signatura rerum’ (1622). Thus despite an initial protestation in his ‘Aurora’ not to be mistaken for an alchemist, Boehme nonetheless subsequently expounded at length a conception of rebirth that went far beyond what he would have been familiar with through Luther’s Bible translation. On Zuber’s reading, Boehme’s spiritual alchemy was “intricately connected not only to the daily experience of the believer, but also to salvation history from the first week of creation to the resurrection of the dead at the Last Judgement”. Central to this drama was the ‘Incarnation of Christ’, with the life of Christ serving as emblematic of an alchemical process (58, 68). Chapter four moves on to Boehme’s biographer, the Silesian nobleman Abraham von Franckenberg (1593–1652), himself a prolific author, even if—as Zuber acknowledges—his “later works do not dwell on spiritual alchemy” (69). Nevertheless, Zuber suggests that Franckenberg’s ‘Theophrastia Valentiniana’ (1627), ostensibly a sympathetic account of the second century Gnostic heretic Valentinus, was, “to a significant extent”, “a study or paraphrase of Boehme’s spiritual alchemy” (74). As for Boehme, so for Franckenberg the Incarnation of Christ and the notion of spiritual rebirth were key. All the same, Zuber notes crucial differences between the two men’s understanding of spiritual alchemy. Franckenberg is followed by a chapter on his spiritual son Georg Lorenz Seidenbecher (1623–1663), whom he instructed not just in Boehme’s teachings but also devotional literature and Hermetic writings. Consequently Seidenbecher served as Franckenberg’s scribe, copying several texts including the cryptic ‘Kabbalistic Regimen’ which Zuber regards as “the description of a process of, or a recipe for, spiritual alchemy” (104). Unsurprisingly, Seidenbecher was subsequently portrayed in an antagonistic source as a “heretical millenarian and Rosicrucian sympathiser” (87).

Among Seidenbecher’s correspondents was the one-time Lutheran pastor Friedrich Breckling (1629–1711) who, together with a multi-volume German edition of Boehme’s works printed at Amsterdam in 1682, is the subject of chapter six. Here, Zuber convincingly argues that Johann Georg Gichtel (1638–1710) should not be given sole credit for this massive publishing project. Rather his contribution was minor, building upon the labours of several lesser known collaborators. Among them, seemingly, was Breckling, who may have served as a proofreader and whose own treatises from 1682—particularly Christus mysticus, sol et sal Sapientiae—indicate a familiarity not just with Boehme’s spiritual alchemy but also writings by Heinrich Khunrath (1560–1605) of Leipzig and Robert Fludd (1574–1637) of London. Combined with his other literary activities, not to mention sympathy for a number of religious nonconformists over the years, Breckling was able, in Zuber’s estimation, “to create one of the richest repositories of sources on German religious dissent throughout the seventeenth century” (123). Among them was Bartholomaeus Sclei’s Theosophische-Schrifften [Theosophical Writings] (Sclei 1686) to which Breckling made additions. Together with an index, which may have been compiled by the translator Loth Fischer (d. 1709) of Utrecht, these editorial interventions suggest the inclusion of spiritual alchemical content into Sclei’s work and that readers were guided to relevant passages. Even so, the spiritual alchemy presented in Breckling’s 1682 treatises appears to “lack a crucial component”, namely “its physical, bodily consequences” (137).

In the eighth chapter, Zuber discusses the Nuremberg-born writer Dionysius Andreas Freher (1649–1728), who spent much of his life in London, where he became associated with Jane Lead and the short-lived Philadelphian Society. Freher was a follower of Boehme—albeit with a “more limited grasp of alchemy than Boehme, Franckenberg, and Breckling” (147). Indeed, Zuber disparages Freher’s “almost complete lack of familiarity with alchemical literature and laboratory practice” (151). As for the last two chapters of Spiritual Alchemy, these deal with Mary Anne Atwood, née South (1817–1910), author of A Suggestive Inquiry into the Hermetic Mystery (1850), which Zuber argues was “a direct descendent of Boehme’s theosophy and its focus on rebirth” (170); and with the early reception history of Atwood’s Suggestive Inquiry.

In sum, this book is extremely good on the reading habits of its main protagonists, their social networks and how the texts under discussion were disseminated in a variety of contexts across geographical and temporal boundaries. But at the same time, it is regrettably a little thin on providing evidence for sustained engagement with spiritual alchemy in the milieus inhabited by Boehme’s predecessors and followers. For these fascinating intertwined threads leave the impression, to my mind at least, that they were not always a dominant aspect in the evolving thought of the figures examined here. Nonetheless, Spiritual Alchemy remains a significant contribution to the field which will rightly prompt a great deal of reflection, even reconsideration, of the currently prevailing ‘New Historiography of Alchemy’.