Christine Caldwell Ames offers a comparative analysis on “medieval heresies” in Christianity, Judaism and Islam. By providing this perspective, she fills a gap in the existing research, and thus her book is highly welcome. The existing and extensive literature dealing with “heresies” mainly focuses on movements or ideas within one single religion and is less interested in interreligious perspectives. Ames’ book is not conceived as a groundbreaking publication, but rather as an “introduction” for “advanced students and faculty” (according to the statement from the publisher). With this in mind, the abstention from the analysis of primary sources is acceptable.
In the introduction, Ames deals briefly with the definition of heresy and the problems raised by the comparative approach. The next five chapters are in chronological order, beginning with the period from 318 to 661 and ending with the years between 1328 and 1510. The main groups, generally considered as “heretics” from an orthodox perspective, are present, such as the Manichaeans or the Cathars in a Christian context.
In her comparative approach she tries to treat the three religions equally: each of them constructed its own “heresies” and its own tradition of their persecution. Ames does not create categorical differences between Judaism, Christianity and Islam. The book is very strong where it transgresses the strict boundaries between these three religions. Even if it is not designed as a contribution to scholarly research, it nevertheless opens new questions in this field. I would like to hint at one interesting observation which merits further discussion, the thesis that Byzantine, Jewish and Muslim “heretical” traditions preceded Western ones (e.g. pp. 5 and 327). Up to this point, the book provides helpful information and otherwise lacking comparative perspectives.
Nevertheless, the book has many weak points: To start with, there is a basic, but severe, problem concerning the cited literature. Non-English texts are remarkably absent. Without knowing German and French literature on the Cathars it is impossible to write an adequate history of this group; consequently, many new perspectives from the last ten years are simply absent. Even pertinent English literature is sometimes missing, e.g. in the case of Byzantine iconoclasm, Brubaker’s and Haldon’s reference work. Secondly, the main methodological tool, the technique of comparison, is employed only to an extremely small extent; the respective part of the introduction (pp. 15ff.) is limited to examples. Practically all systematic literature is missing and not one title from the debates in religious studies is mentioned. But in an introductory book, an in-depth reflection on the concept of comparison is indispensable. Other problems, which I indicate below, stem from this major deficiency. Thirdly, the discursive construction of heresy, even though it is discussed in the introduction (pp. 6–8), is not problematised sufficiently. Ames proves to be aware of one of the main problems, namely the normative impact of terminology (e.g. the process of production of the label “heresy” or the debate concerning the “guilt” connected with the violent persecution of “heretics”), but the consequences for her analysis are often missing. For example, the heretisation of the Karaites by the rabbinic tradition ought to be problematised in a scholarly perspective. Even more surprising (and questionable) is the labelling of the Jewish Karaites as “heretics”. Fourthly, the chronological order is not convincing. It is mainly based on Western history and, consequently, often not applicable to other traditions. Again, the Karaites exemplify the problem: There is no justifiable reason to split them into three chapters (pp. 113ff., 175ff., 283ff.). A comparative perspective of history demands more complex models of periodisation. Fifthly, the terminological differentiation is weak. Ames does not systematically discuss either the difference between theological terms such as heresy and schism (only insufficiently, p. 6) nor the sociological question to what extent heresy and difference are equivalent. The consequences can be seen in the treatment of the Waldenses (pp. 154–158), who are listed in a chapter on “medieval heresies” beneath the Cathars. Of course, it is possible to eliminate the difference between the Waldenses and the Cathars from a sociological perspective, but it would be necessary to reflect on the conceptual differences which these groups created between themselves and with regard to the “orthodox” church. Sixthly, the important scholarly debates on the cultural contexts of “heresies” are only partly present. Ames discusses, for example, Moore’s thesis of the mediaeval Western world as a “persecuting society”, but other controversies (e.g. the consequences of monotheism for religious pluralism) are missing. This problem is applicable to many other debates.
My summary evaluation remains ambivalent: Ames’ book fills a lacuna not only by serving as an introductory textbook for students. On the other hand, its basic deficiencies are striking; the systematic discussion is superficial and the description of historical processes often does not reflect the current scholarly research.
 Leslie Brubaker / John Haldon, Byzantium in the Iconoclast Era, c. 680–850. A History, Cambridge 2011.
 E.g. Thomas A. Idinopulos / Brian C. Wilson / James Constantine Hanges (eds.), Comparing Religions. Possibilities and Perils?, Leiden 2006.
 Robert Ian Moore, The Formation of a Persecuting Society: Authority and Deviance in Western Europe, 950–1250, Oxford 2007.