It is a commonplace that Interregnum England seethed with new religious groups, many of which were inspired by earlier mystical writings and contemporary spiritualistic groups like the Family of Love. Founded in the sixteenth-century Netherlands by Hendrik Niclaes, the Familists became a major carrier of mysticism in Protestant England. Liam Peter Temple has now provided a broader, cross-confessional perspective to this phenomenon that moves well beyond the Familists and their heirs. By extending the study of these unconventional religious streams through the entire century, he seeks to comprehend the changing face of mysticism and its public perception by its practitioners and opponents, and how, over the course of the century, polemicists transformed attitudes toward this ancient approach to religious experience from respect to derision. Thanks to Protestant attacks especially, by 1700 mysticism had become an outlier to England's institutional churches. This was due, Temple notes, to three major factors. First, mysticism's non-confessional, at times anti-confessional, implications were condemned by denominational proponents on all sides. Second, any association with Catholicism, real or implied, was readily demonised as association with the realm's enemies, and Temple reveals the centrality of Catholic forms of mysticism and their texts to its English proponents. And third, the perceived excesses of the sectarian explosion of the 1640s and 1650s led many learned writers to condemn all forms of spiritual enthusiasm as conjoined with irrationality and sectarianism, hence as contrary to the new scientific or enlightenment discourse. These were problems that, despite the support of continental Pietists, post-1650 mystics had little chance to overcome.

Temple's clearly organised monograph is divided chronologically into five chapters, beginning, interestingly enough, with English Catholic mystics instead of the Familists, whom polemicists constantly blamed for the rise of mystical sects during the Civil War. Instead, Temple closely examines the mysticism of English Catholic Benedictines who had taken refuge on the Continent. He shows that one of the central texts for mysticism in the second half of the seventeenth century was the Sancta Sophia of Augustine Baker, spiritual advisor to the Benedictine nuns of Cambrai. While only published post mortem in 1657, Baker's manuscripts circulated widely in mystical circles during his life, and many of his associates feared that his mysticism might encourage disorder; later critical readers fretted that they may have led to the excesses of the Ranters and Quakers.

Temple turns next to the mystical currents within the Puritan movement before and during the Civil Wars, focusing on Francis Rous, who incorporated mystical experience within his predestinarian Calvinism, and the London radical preacher John Everard, who emphasised, like the Familists, spiritual perfectibility. Temple's discovery that such Protestant nonconformists found Catholic mystical treatises like the Theologia Germanica or the works of the English Recusant Benet of Canfield inspiring, challenges us to reevaluate how we imagine confessional boundaries. Simply put, apart from Familist publications, there were very few non-Catholic mystical works available to English Protestants, for the influential works of the German spiritualists Sebastian Franck or Casper von Schwenckfeld, or the Dutch David Joris (George), were rarely translated, if at all. This reliance on Catholic sources, Temple argues, became a major problem for the mystically inclined after the Interregnum.

Temple follows this intriguing thread by examining the adverse perception of mysticism on the part of English churchmen over the middle decades of the seventeenth century. This negative reaction was understandable, as the harnessing of mysticism by Familists and Ranters ‘challenged a wide range of societal norms and ecclesiastical structures’ (p. 77). Mainstream writers thus sought to cut the feet out from under such unconventional religiosity. Using medical terminology, they asserted that those who claimed mystical experiences were instead suffering from ‘religious melancholy’, a humoral condition adversely affecting the mental state of patients so that they would interpret hallucinations as visions, and in a state of alleged religious ecstasy fall into emotional excess and irrationality. As developed by Protestant writers Robert Burton and Meric Casaubon, and further honed by the Cambridge Platonist Henry More, this diagnosis discredited both Catholic and sectarian claims to special sanctity. Religious enthusiasm, once central to the Christian tradition, was now a form of illness leading to extremes of belief and behaviour.

This negative portrayal of mysticism had injurious effects into the eighteenth century for, try as they might, mystics such as the Benedictine Serenus Cressy (chapter iv) or Jane Lead and her fellow Philadelphians (chapter v) could not overcome this powerful depiction of mystics as irrational and potentially seditious. Perhaps even more powerful was the use of satire and mockery to critique mysticism; by the late seventeenth century, intellectuals were laughing at the practice, rather than taking it seriously. Temple concludes that the Philadelphians’ efforts to craft a spiritual or mystical counterpoint to the Enlightenment's emphasis on reason crumbled under the mockery. Their critics also criticised them for their alleged Familist roots and their un-English reliance on the writings of continental mystics like Jacob Boehme, the French prophets and German Pietists.

As Temple deftly reveals how English elites shifted from positively appreciating mysticism's spiritual value to mocking it as mental illness, he highlights the importance of Catholic sources for both sectarian and Protestant spiritualistic groups. While he also acknowledges the importance of cross-Channel influences for the later period, more research is needed into this feature for the first half of the century. The translated Familist literature, for example, proved remarkably long lived, and even when English writers did not have any of Joris's works in translation, they were deeply concerned about his ideas. For example, around 1650 Henry More used the melancholia diagnosis to discredit Niclaes's and Joris's spiritualism, even without a single Joris promoter in England. More, seeking to balance reason and spirituality, feared that such continental mysticism would push the English into irrationality. Temple's study thus reveals the polemical characterisation of mysticism as part of England's confessional conflicts, and how continental influences inadvertently played into those polemics. These cross-confessional and cross-Channel aspects of the story need more scholarly attention, and Temple's groundbreaking study should inspire such a quest.