* The American Historical Association's Guide to Historical Literature, Third Edition (Oxford University Press, 2003)
* The Origins of the Great War: A Documentary History (co-edited with Christopher Clark and Peter Wetzler) (Cambridge University Press, 2013)
* Europe, 1815-1870: Nations and Revolutions (co-authored with William C. Lowe and Steven C. Hause) (Oxford University Press, 2014)
* World War I: A Very Short Introduction (Oxford University Press, 2014)
* The German Army in the First World War (Cambridge University Press, 2018)
* The Hohenzollerns: A Dynasty in Conflict (Oxford University Press, 2022)
Articles and chapters in books:
* "The German Historical Profession and Historical Consciousness after 1945" in History and National Life (co-edited with David C. Large) (Berghahn Books, 1995)
* "The Hohenzollerns and National Identity in Prussia, 1871-1918" in Nation and Identity in Historical Perspective, edited by Stuart P. M. Mackintosh (Palgrave Macmillan, 1998)
* "The Schlieffen Plan and German Intelligence in the Coming of the First World War" in The Journal of Modern History (2000)
* "World War I and the Transformation of European Politics, 1914-1945" in The Oxford Handbook of Modern European History, c. 1700-c. 2000, edited by Christopher Clark (Oxford University Press, 2009)
* "1914: Why Britain Went to War" in BBC History Magazine (2014)
* "The German Invasion of Belgium: A Crime against Europe?" in The Journal of Modern History (2015)
* "World War I and the Making of the Modern World" in The Oxford History of the United States (Oxford University Press, 2017)
* "The Long Road to War: The Origins of World War I" in The First World War: A New Global History, edited by Michael S. Neiberg and Peter L. Hahn (Oxford University Press, 2019)
Other writings:
* zahlreichen Rezensionen und Aufsätze für Fachzeitschriften
* Beiträge für Zeitungen und Magazine, wie Die Zeit, Der Spiegel, Die Tageszeitung und Le Monde
* Vorträge und Interviews für Rundfunk und Fernsehen