Readers of this Journal will not be surprised that early modern Englishmen were unsettled by new religious opinions. Most polemicists sought in response to cast the proponents of new ideas as heretics, even to demonise them, while those so accused tried to defend themselves and deflect such charges. The resulting literary productions could sometimes be inventive and imaginative, as Loewenstein argues, and the predictable outcome was a heightening of anxiety and tension. In the first half of Treacherous faith, Loewenstein uses a series of case studies to remind us of the contours of this process in the sixteenth century, focusing on authors like Thomas More and John Foxe. Loewenstein then turns to ‘Milton's England’, describing the outrage of Presbyterian ministers at the proliferation of heresy and the strategies used by religious Independents to critique what they saw as persecution. Loewenstein's sympathies lie with the latter and he insists upon the tensions and instabilities of the persecutors (notably More) and the sophistication of those who ‘interrogated’ the prevailing cultural paranoia (Anne Askew, John Milton). The argument is based largely upon extracts from the texts themselves; the philosophical and theological context is sketched only lightly and the canvas is too broad to allow for much close reading. Loewenstein's views are, therefore, unlikely to alter scholarly opinion, but perhaps academics are not Lowenstein's primary intended audience. Indeed, throughout the book his concerns about contemporary polemical culture – his fears that the ‘heresy-mongers’ have not yet been defeated – come though clearly. He notes that William Prynne's campaigns against heresy ‘could be considered analogous’ to McCarthy's rhetoric in the 1950s (p. 222) and the book ends with a warning that our world still suffers from the ‘blight of religious conflict, demonizing and paranoia’ (p. 348), forces that were so disruptive in early modern England.