The history of Jewish liturgy is a subject that Ruth Langer, within the sphere of Jewish studies in North America, has made peculiarly her own. Her other long-established interest is in Jewish-Christian relations. In this book, as in other recent publications, she has brought these two interests together. The liturgical benediction (berakhah) which is the focus of this study, the Birkat haminim, has often been interpreted as in origin a Jewish execration of Christians, and in the Middle Ages it was indeed understood by Jews in this sense. Since the Enlightenment and the rapprochement between Jews and Christians in western Europe and North America it has been interpreted differently, and its text has been revised so as to avoid seeming to reflect or fuel antagonism towards Christians. In fact, from the earliest attested formulae to the most recent it has been subject to constant modification, and from the point of view of liturgical history the major contribution of the book is the collection of dozens of versions, derived from hundreds of sources, and all carefully differentiated and collated. It attempts to reach out to a wider readership by placing this protean prayer within successive social and intellectual contexts, such as the mysticism of the kabbalah or the rationalism of assimilated, bourgeois Liberal Judaism, with its heightened sensitivity to liturgical language that might give offence to Gentile visitors. These contexts are carefully explained, with special reference to the process of liturgical reform. The book is not an easy read, since at its core is a highly technical textual and diachronic study of the vicissitudes of a Hebrew prayer text, and it is in these terms that it must stand or fall. The intended audience thus consists primarily of specialist students of Jewish liturgy, and secondarily historians of Judaism more broadly. The choice not to engage with liturgical scholarship in a more general way, or with the parallel history of Christian liturgical reform, while understandable in a book which is very dense and substantial as it is, will inevitably limit its appeal to those outside the charmed circle of Jewish studies.