Christoph Schmidt is a renowned scholar of church history in Eastern Europe, especially with regards to the Russian Empire. In his religious history of Eastern Europe, he presents a broad panorama of different religions and religious denominations, all of which shaped this region. However, this is where the problems begin. Schmidt explains at no point what he defines as "Osteuropa", although he is explicitly using this term instead of the much more flexible "Eastern Europe", which has become popular in German academic discourses as well ("Östliches Europa"). Implicitly, the book focuses on the main fields of the authors' previous research projects, covering a somewhat undefined area within the eastern part of Rzeczpospolita, nowadays western Ukraine, Belarus, and western Russia. However, he also makes some excursions to the Baltics, Balkans, Caucasus or Central Asia. Consistency is not Schmidt's main priority – quite the contrary, his book represents a rather subjective, intellectually demanding chain of associations that somewhat implicitly attempts to tell the story of secularization from the early Middle Ages to the 1990s.
The book is divided into three parts. In his introduction, Schmidt claims that his aim is to present the "ups and downs of religion and religious history as a whole" (p. 7). Subsequently, he sets forth ten hypotheses representing the main issues of his book and simultaneously provides a short and intriguing introduction to religion as an international field of research in the twentieth century. In his seventh hypothesis, he emphasises the importance of micro-historical studies as a key to gain insight, at least to some degree, into everyday religious practice far away from normative theology and theory. The example of Emmaunel Le Roy Ladurie's Montaillou, however, is poorly chosen. After its publication in 1975, this book had been criticized for its lack of a critical examination of the underlying source material.  Schmidt's choice is therefore ironical in two ways: First, his narration often gets lost in macro-historical, sometimes even dubious causalities that are missing a pragmatic, micro-historical perspective. Secondly, Schmidt himself is not free from methodological mistakes when dealing with some of his sources, as shall be discussed below.
The second part of his book is supposed to be an introduction to the different forms of religion in Eastern Europe. He deals with very early forms of shamanism, the two main Christian denominations in this area (Roman Catholic and Eastern Orthodox), as well as with the two other Abrahamic religions, Judaism and Islam. A short outlook into central Asian Buddhism is added, while other denominations such as the Armenian rite are totally missing.
Surprisingly, the third part of his book is almost entirely focused on the Roman Catholic and the Eastern Orthodox Church and its entanglements with Judaism. It focuses on the history of this relationship from the middle of the fifteenth to the twentieth century, as well as on the specific phenomena of Eastern European religiousness, such as the disputes between the Reformation and the Counter Reformation within the Polish-Lithuanian Commonwealth. Furthermore, the author retraces the shaping of the eastern Catholic Church and the "backlash" towards traditionalism in the orthodox and Jewish communities. In spite of his awareness that a simple teleological process towards secularism is not accurate (see p. 23), he more or less follows that kind of narrative: the spreading of the Enlightenment in all Abrahamic religions – even though Islam is only incidentally mentioned – is his main argument throughout the book. He then closes his narration with the "return" of the newly nationalized religions in Russia and Ukraine in the 1990s, but Schmidt apparently does not come to the conclusion that his teleological way of storytelling might be worth revising.
Schmidt's book is a treasure chest of knowledge and very fascinating episodes. As enlightening as it is, however, it is also irritating and leaves its readers somewhat undecided: Did Schmidt intend to write an introduction to religious history of Eastern Europe? For this purpose, the book requires its readers to have far too much previous knowledge to follow this associative approach. The glossary at the end is no big help to provide at least some orientation, either. Likewise, the literature provided in the endnotes seems more or less haphazard, the selection of further readings is not commented on and disorganized, and the index is far from complete and focuses on persons only.
In general, the book reads like an overlong essay, but often lacks the courageous and trenchant style for such a genre; quite the contrary, it gets lost in details. Considering the large geographical and chronological frame, it is obvious that not everything can be told in detail. For instance, the role of the Northern Wars for the triumph of Jesuit Catholicism in Poland-Lithuania remains quite underemphasised. Schmidt could have added some of the latest research on the Polish-Lithuanian Commonwealth by Hans-Jürgen Bömelburg , Karin Friedrich , Michael Müller  or Yvonne Kleinmann , to name just a few relevant scholars in the field. More severely – regarding his aspiration to write a micro-history of religion and not of the church(es) or politics – weighs his total lack of coverage of everyday religious experience during this time.
Another example for the book's shortcomings is that Schmidt explains the diverse Reformation processes in Europe solely on a macro-historical level by a country's geographical distance to Rome (p. 128). In my opinion, not many scholars of early modern history would agree with this simplification. Even more indigestive, considering contemporary academic standards of a reflective choice of words, is his totally uncritical usage of terms like "ethnicity", "tolerance" or "Ukraine" and "Weißrussland" when writing about early modern times.
As far as Polish history is concerned, Schmidt seems much more fascinated by the survival of Catholicism during Soviet Rule than by the medieval period. In his paragraphs on the spread of Christianity in Poland, he falls for the narrative of Gallus Anonymus without any critical remark on the source material (pp. 54 ff., 128). He even calls him "Martinus Gallus" (p. 54), which has gone out of academic fashion since the ninetenth century. This is not the only instance where Schmidt uses translations of old historiographical sources without providing any critical contextualisation.  Whereas this can be discarded as only a little imprecise according to the literary standards of an essay, he is just plain wrong when describing the Magdeburg Law as having been given to the Jewish community in Lviv in 1356 (p. 90).
This total misunderstanding highlights an aspect most surprisingly missing in his book: He often states that Eastern Europe was characterized by a multitude of different religions and confessions. However, he barely describes the consequences of living side by side. His narrative stays on the level of elitist interactions and debates, he divides more than he entangles. By choosing to focus on different religions in each chapter separately, many aspects like the Black Madonna of Częstochowa or religious figures such as Ba'al Shem Tov or Piotr Skarga are mentioned repeatedly without ever combining them into a greater picture. Maybe a chronological approach would have been more suitable for his task after all.
Besides these problematic aspects, the book has been proofread poorly. A lot of spelling mistakes, partly missing Polish diacritics as well as the already mentioned thin register add up to the somewhat unfinished overall impression of the book. Nevertheless, Schmidt presents a broad invitation to further and much needed scholarly discussion that does not keep its limits to one religion or religious denomination, but presents them as an entangled and transnational phenomenon in Eastern Europe and beyond.
 See Kathrin Utz Tremp, Von der Häresie zur Hexerei. "Wirkliche" und imaginäre Sekten im Spätmittelalter, Harrasowitz 2008, pp. 59-66.
 Cf. Hans Jürgen Bömelburg (ed.), Polen in der europäischen Geschichte. Ein Handbuch in vier Bänden, Bd. 2: Frühe Neuzeit, Stuttgart 2011; idem, Katholische Konfessionskulturen in Polen. Ein Vergleich von Ordnungsvorstellungen in der zweiten Hälfte des 17. Jahrhunderts (1648-1721) und der zweiten Hälfte des 19. Jahrhunderts, in: Johannes Gleixner et al. (eds.), Konkurrierende Ordnungen. Verschränkungen von Religion, Staat und Nation in Ostmitteleuropa vom 16. bis zum 20. Jahrhundert, München 2015, pp. 21-45.
 Cf. Karin Friedrich, The Other Prussia. Royal Prussia, Poland and Liberty, 1569 –1772, Cambridge 2000; idem, Konfessionalisierung und politische Ideen in Polen-Litauen, in: Joachim Bahlcke (ed.), Konfessionalisierung in Ostmitteleuropa: Wirkungen des religiösen Wandels im 16. und 17. Jahrhundert in Staat, Gesellschaft und Kultur, Stuttgart 1999, pp. 249-265.
 Cf. Michael G. Müller, Toleranz vor der Toleranz. Konfessionelle Kohabitation und Religionsfrieden im frühneuzeitlichen Ostmitteleuropa, in: Yvonne Kleinmann (ed.), Kommunikation durch symbolische Akte. Religiöse Heterogenität und politische Herrschaft in Polen-Litauen, Stuttgart 2010, pp. 59-75; ders., Religion oder Rebellion? Konfessionsstreit und innerstädtische Konfliktaustragung in Danzig und Marienburg um 1600, in: Unterwegs in Europa. Beiträge zu einer vergleichenden Sozial- und Kulturgeschichte. Festschrift für Heinz-Gerhard Haupt, hg. Christina Benninghaus, Frankfurt a.M. 2008, pp. 163-181.
 E.g. Dietlind Hütchker, Martina Thomsen, Yvonne Kleinmann (ed.), Reden und Schweigen über religiöse Differenz. Tolerieren in epochenübergreifender Perspektive, Göttingen 2013; Yvonne Kleinmann, Städtische Gemeinschaft. Christen und Juden im frühneuzeitlichen Rzeszów, in: Osteuropa 62, 10 (2012), pp. 3-23.
 Another instance would be the chronicle of Thietmar of Merseburg, from which Schmidt cites without any further remark (p. 54), he also gives no proof of any of the charters he discusses (e. g. pp. 57, 89-91), and the problem of the Montaillou example has already been discussed above.