In the literature of the Holocaust history, ‘bystander’ is still a term open to conceptual clarification. Addressing deep human feelings and daily behaviours, ‘bystander’ made its first appearance as an analytical concept in Holocaust literature through the work of Raul Hilberg. Through their edited volume Probing the Limits of Categorisation: The Bystanders in Holocaust History, Christina Morina and Krijn Thijs engage in the challenging work of advancing the knowledge about bystanders’ thoughts and actions by exploring several specific historical contexts, both in Nazi Germany and in various occupied countries across Europe. The volume offers an excellent display of theoretical and conceptual approaches, research methodologies and case studies. Moreover, this volume poses a number of challenging research questions that encourage further work in this promising field. It starts with Mary Fulbrook’s chapter which performs an excellent theoretical and critical review of the bystander concept. Fulbrook’s contribution serves to set up the research context of this volume by exploring the ‘bystander’ in the context of action, time, and location within the genocidal evolution process. Acknowledging Hilberg’s conceptual triad, Fulbrook concludes that coupling this analysis of bystanders with a differentiation of ‘perpetrators’ might bring a ‘seismic shift in historiography’ and fill in the research gaps not only in Holocaust history but also future dynamics of violence. In the following chapter, René Schlott takes us into the world and work of Raul Hilberg by reconstructing the history of the ‘bystander’ concept and ushering readers though Hilberg’s personal experiences with bystanders in interwar Vienna and discussing the research challenges of ‘discovering’ this concept.

Scholars interested in the conceptual and research methodological approaches to bystanders will find great sources of research inspiration in a number of chapters. Timothy Williams introduces a typology of actions in genocide built on two dimensions, impact, and space, and he exposes the diversity of individuals actions during the Holocaust. Readers will discover the rich research potential this analytical typology carries through a reflection on the Cambodian genocide. Froukje Demant investigates bystanders from social-scientific approaches and explores interesting parallels between two case studies: micro level bullying in classrooms and Jewish/non-Jewish relationships in the German-Dutch borderland from 1933 to 1941. The socio-psychological investigation mechanism reveals significant insights into bystanders’ decision-making and behaviour processes. Christina Morina uses a valuable, but surprisingly overlooked source for Holocaust research, diaries, to examine bystanders’ reactions toward the fate of their Jewish compatriots. By analysing these chronological sources, the author exposes the complex social processes which influenced how the bystanders acted and the subjunctive solidarity they manifested.

Several chapters move beyond the purely theoretical and conceptual to offer close analyses of bystanders in Nazi Germany and various occupied countries across Europe, further underlining the importance of the research presented in this volume. Investigating the Polish case, Jan Grabowski addresses the bystander concept in the Eastern European context. Highly overlooked during decades of censorship, the history of Eastern Europe is in need of further research when it comes of bystanders for two main reasons: it is the territory where the vast majority of Jews lived and the level of terror instituted in the occupied countries by Nazi Germany is incomparable with its Western equivalent. Jacques Semelin addresses the survival of Jews in France through a novel multifactorial analysis. This approach discusses how bystanders’ ‘social reactivity’ could affect Jewish victims. Starting with a literature review on the bystander in recent Dutch history writing, Remco Ensel and the late Evelien Gans propose an investigation of the social and psychological mechanisms which distanced Jews from the bystanders in the context of The Netherlands’ pre-occupation, occupation, and post-occupation periods. The Dutch experience is also the subject Krijn Thijs’ critical dissection of the widely publicised 2012 book ‘Wij weten niets van hun lot.Gewone Nederlanders en de Holocaust (‘We don’t know anything about their fate.’ Ordinary Dutchmen and the Holocaust). Challenging the main arguments against the ‘myth of the guilty bystanders’ that underpin this earlier work, Thijs offers a fresh perspective on Dutch bystanders during the Holocaust.

Those interested in comparative research will draw inspiration from Bart van der Boom’s contribution to Probing the Limits of Categorisation, which demonstrates through the comparison of two opposing case studies – The Netherlands and Denmark – that the dramatically different deportation rates cannot be explained by the mindsets of bystanders, as these two cases were very similar.

The volume also considers research into visual representations of bystanders. Their ‘hidden’ world during the Holocaust is revealed in a thought-provoking way across a number of chapters. Roma Sendyka investigates the bystanders as visual subjects and places her case studies in occupied Poland. Performing an analysis on the works of two visual artists, Sendyka reveals the complexity of visually representing bystanders and the research needs of this approach. Wulf Kansteiner addresses representations of bystanders on the West Germany television across four overlapping stages of Holocaust. This chapter demonstrates how only recently, sixty years after the events, the role of ‘ordinary men’ in the genocide has finally received attention. Susan Bachrach examines another visual display of bystanders at the United States Holocaust Memorial Museum. While integral to USHMM’s exhibition since its inception, bystanders are the central figures of the ‘Some Were Neighbours’ exhibition, the installation building of which demonstrates some of the challenges of addressing the bystanders: the literature in the field, the geographical areas, the visual representation.

Three chapters study the fine and sometimes blurry lines between perpetrator and bystanders. Adam Knowles exposes Martin Heidegger through his Black Notebooks and reveals Heidegger as an active perpetrator in his roles as Rector and professor in the context of his refusal to be labelled as a bystander. Christoph Kreutzmüller identifies the bystanders in the photographs taken during the pogrom in Baden-Baden on November 10, 1938. The author concludes that the dividing lines between ‘bystanders’ and ‘perpetrators’ are not as clear-cut as the concepts indicate due to their links and overlap in social functions. Susanne C. Knittel offers a reading of SS wives involvement in National Socialist politics and crimes. Placed in the context of a theatrical performance ‘The Woman at His Side: Careers, Crimes, and Female Complicity under National Socialism’, Knittel provides an intriguing introduction into the world of self-representation after 1945 and concludes that bystanders can also be understood as figures of potentiality holding the hope that things could have been otherwise.

The volume concludes with two epilogues. Norbert Frei argues that in order to gain a more comprehensive understanding of the bystander, this figure as a social phenomenon in Nazi Germany should be coupled with its post factum invention as a historiographical figure. Ido de Haan rounds off the volume with a summary of the main findings grouping them into three categories: the bystander as a history figure; as an analytical figure; and, last but not least, as a moral figure.

This rich, multidimensional book makes a significant contribution to our understanding of the limits and difficulties of categorising bystanders. It advances the field and, crucially, provides a roadmap for future research into this complex, unsettling figure, not just during the Holocaust, but also beyond.