Recent scholarship has discovered the aftermath of the First World War as a time of ethnic strife and paramilitary upheaval. Whereas the period 1917–1921 in Russia is well known and well researched as an era of civil war, the conflicts that shook central Europe after its various states had gained national independence in late 1918 were largely ignored or, at least, not regarded as part of one transnational phenomenon. Because these nation-states defined citizenship mostly along ethnic lines, their struggles for the borderlands and resident populations were accompanied by forms of interethnic violence that are typical of civil war scenarios. Between 1918 and 1920, no ethnic group in central and eastern Europe suffered more fatalities than the Jews.

This last fact, at least, is well known, but until William W. Hagen's impressive study, it was far from being systematically researched, let alone analyzed, although various explanatory attempts appeared immediately after the relevant events. When news of Polish soldiers plundering, raping, torching, and killing in Jewish communities in eastern Polish lands went around the globe in early 1919, the reborn Polish state was accused of pursuing a policy of targeted extermination in the borderlands. Yet, as contemporaries such as the first US minister to Warsaw, Hugh S. Gibson, or the former U.S. ambassador to the Ottoman Empire, Henry Morgenthau Sr., noted on closer examination, the antisemitic riots and murders arose from a variety of motives, but were not ordered from above.

For William H. Hagen, these attacks did not come out of the blue. Already early in the First World War, the Russian army established itself as an occupying power in what were then called the Polish Lands—to be precise, Galicia—and displayed structural as well as “wild” antisemitic violence. That is why this study begins as early as 1914, and it is important to note in this context that, whereas a Polish national army at that time did not exist, many of the czarist soldiers spoke Polish. However, antisemitic stereotypes and superstition deeply rooted in the Polish-speaking population went back much further. These strongly influenced the events that followed, especially in the aftermath of the First World War, but have hardly been investigated to date—except by Hagen himself—in connection with the pogroms of 1918–1920.

It is precisely this aspect that makes Hagen's work a groundbreaking study. Based on an impressive body of sources, he demonstrates how, in most cases, the Polish-speaking local population participated in pogroms that had been initiated by Polish soldiers. Evident is a mixture of motivational and situational factors that combined to form an explosive mixture during the First World War, not only in Poland. Material hardship, brutalization, popular antisemitism, and a power vacuum created by the decline of empires led to catastrophe, where larger groups of people—mostly men—had direct access to weapons and national governments were not yet able to control them. In this regard, Hagen's book often asks questions similar to those posed in Holocaust studies such as Christopher Browning's Ordinary Men (1992) or Timothy Snyder's reflections on the connection between statehood (or rather its absence) and violence in Bloodlands (2010) and Black Earth (2015).

Although Hagen hints at such connections, he does not succumb to the temptation to present a large-scale comparison between the First and Second World War. Instead, he presents a fact-founded and detailed case study on which such future studies can build. In this regard, his take on what he calls “popular antisemitism” deserves closer examination. Because the nationalist idea had not won much ground in the Polish countryside by 1918, rural acts of antisemitism seem not to fit into the pattern of ethno-nationalist violence instigated by the writings of right-wing ideologues such as Roman Dmowski. As Hagen convincingly shows, unlike nationalism, rural antisemitism was not born in the nineteenth century, but went way back to medieval times. In an ever more rapidly changing world, rural Jews were increasingly perceived as a threat by Polish peasants. At the beginning of the twentieth century, Catholic priests in particular ensured that both antisemitic currents converged in the minds of the rural population. Then, in 1918, Polish soldiers and peasants combined nationalist and popular antisemitism in an aggressive assault on the Jewish communities in Poland.

Contrary to the views of many contemporaries, these Jewish communities were extremely heterogeneous. Assimilated upper-middle-class city dwellers and Zionists in the cities contrasted with one another as well as with Orthodox Jews and small traders in the shtetls. Another merit of Hagen's study is that he not only points out these complexities, but also includes them in the analysis. He offers us a detailed picture of Polish society on the verge of independence, which had fallen into Poland's lap completely unexpectedly and for which the nascent state was therefore not really prepared.

The concentration on the Polish territories naturally comes with a price. Antisemitic violence was not only a salient characteristic of the Second World War. It was already endemic in the years 1918–1921, not only in Poland or in the streets of the Weimar Republic, where the Freikorps murdered Rosa Luxemburg and Karl Liebknecht, but also in Hungary under the White Terror or in Ukraine, which was torn by civil war, where the estimated number of Jewish victims is—contrary to the Polish case with fewer than one thousand murdered Jews—in the hundreds of thousands. A comparative study of this transnational phenomenon is yet to be written. William W. Hagen's Polish case study is an excellent example of how this can be done.