“Arguing against Karl Popper, who regarded conspiracy theories as a product of the eighteenth century, [...] Soyer insists convincingly that they started far earlier, in the early modern period.” Alastair Hamilton, Warburg Institute. In: The Journal of Ecclesiastical History, Vol. 71, No. 2 (2020), pp. 410–412.“compelling and thoroughly researched […]. The author is to be congratulated on an important, and highly recommended, contribution.”Norman Roth, University of Wisconsin–Madison, emeritus. In: Renaissance Quarterly, Vol. 74, No. 2 (Summer 2021), pp. 651–653.“I applaud Soyer’s engagement with a sensitive historical subject like popular antisemitism, without opting to hide behind academic relativism or political correctness. […]. [His book is] solid, convincing, and enrichingly honest.”Claude B. Stuczynski, Bar-Ilan University. In: AJS Review: The Journal of the Association of Jewish Studies, Vol. 45, No. 2 (November 2021), pp. 464–468.“a detailed and fascinating book […], valuable not only for historians but also, and maybe even more so, for people interested in how conspiracy theories work, what they do, and how they endanger ethnic and religious groups.” Lucien van Liere, Utrecht University. In: Exchange: Journal of Contemporary Christianities in Context, Vol. 50, No. 3–4 (2021), pp. 327–328.