My engagement with the issues discussed in this book dates back to the late 1990s. In the wake of my monograph on rural Bavaria from 1914 to 1923, I first came across the Reichsbanner, and discussed its significance in a journal article. At this time, and on many later occasions, I received generous advice from Belinda Davis, Christa Hämmerle, Wolfgang Hardtwig, Bedrich Loewenstein, Josef Mooser and Bernd Ulrich, for which I am extremely grateful. Work on the current book could finally commence after I had joined the University of Sheffield. I have benefited immensely from conversations with friends and colleagues at Sheffield, especially Miriam Dobson, Mike Foley, Ian Kershaw, Miles Larmer and my mentor Bob Moore. I am also grateful to Richard Bessel, Michael Geyer, Thomas Kühne, Thomas Mergel, Helmut W. Smith and Jay Winter for their intellectualism and unwavering support, and for important conversations with Martin H. Geyer, Rüdiger Graf, Daniel Morat, Nadine Rossol and Meik Woyke. Mike Geheran, Patrick Houlihan and Thomas F. Schneider have offered constructive feedback on individual chapters – thanks a lot! Moritz Föllmer and Matthew Stibbe have commented on a draft of the whole book. Both have written trail-blazing books and articles on Weimar Germany, and their work has deeply influenced my own thinking on the subject. Both are also trusted friends, and I owe a lot to their support and generosity.

Also important was the practical and material support I have received along the way. I very much appreciate the valuable support of the staff of the many archives and libraries I have consulted. Special thanks go to my friend Anja Kruke, head of the Archiv der sozialen Demokratie in the Friedrich Ebert Foundation in Bonn; to my former student Alexander Schwitanski, now head of the Archiv der Arbeiterjugend in Oer-Erkenschwick; to Michael Hensle of the Stadtarchiv Schiltach; to Ute Simon of the Stadtarchiv Schmalkalden; and to the staff of the library of the Friedrich Ebert Foundation, of the Bibliothek des Ruhrgebiets in Bochum, and of the Bayerische Staatsbibliothek in Munich. Martin Brost has generously funded the digitisation of Social Democrat journals and newspapers, which are hosted by the online portal of the Friedrich Ebert Foundation. I am extremely grateful for this invaluable resource. Archival research in Germany was supported by a British Academy Small Grant, and facilitated by invitations to work as a Visiting Scholar at Humboldt-Universität zu Berlin and as a Visiting Professor at the Eberhard Karls Universität Tübingen. Ewald Frie, Daniel Menning, Jörg Neuheiser, Sebastian Kraffzig, Lena Gautam, Claudia Prinz, Andreas Weiß and many others turned these trips into convivial occasions. Thanks also to Franz and Joan Brüggemeier for putting me up during a trip to Freiburg! I am grateful to Laura King and Robert Whitelock, who carefully copy-edited my manuscript, and to Conny Schneider, whose diligent work as a research assistant was indispensable. At various stages, James Pearson kindly offered crucial technical support. The Arts and Humanities Research Council has generously supported the completion of the manuscript through a grant in its Fellowship Scheme. Michael Watson, my editor at Cambridge University Press, offered crucial support, and commissioned very helpful feedback by two anonymous reviewers. Permission to reproduce copyright material by the following is gratefully acknowledged: Berliner Vorwärts Verlagsgesellschaft, Archiv der sozialen Demokratie der Friedrich-Ebert-Stiftung Bonn, Bundesarchiv Koblenz, Archiv der Münchener Arbeiterbewegung, Münchener Stadtmuseum and Museum Schloss Wilhelmsburg in Schmalkalden.

Finally, my most heartfelt thanks go to my family: to Christine, Jonathan and Sophie; to my brothers Alexander and Jakob; and to my mother, Susanne Lücke, née Plojetz, who taught me all about the importance of books.