Kaiser's areas of interest include the history and politics of the European Union and transnational dimensions of European and global history since the mid-nineteenth century.
Monographs
The European Ambition. The Group of the European People's Party and European Integration, Nomos (2020). ISBN978-3-8487-6767-0 (with L. Bardi et al.).
Exhibiting Europe in Museums. Networks, Collections, Narratives, and Representations, Berghahn (2014). ISBN978-1-78238-290-4 (with S. Krankenhagen and K. Poehls).
Europa ausstellen. Das Museum als Praxisfeld der Europäisierung, Boehlau (2012). ISBN978-3-412-20888-2 (with S. Krankenhagen and K. Poehls).
with J.-H. Meyer, Eds. (2017, paperback 2019). International Organizations and Environmental Protection. Conservation and Globalization in the 20th century. New York, Berghahn.Publisher's page.
with J.-H. Meyer, Eds. (2013). Societal Actors in European Integration. Polity-Building and Policy-Making 1958–1992. Basingstoke, Palgrave Macmillan.
with B. Leucht and M. Gehler, Eds. (2010). Transnational Networks in Regional Integration: Governing Europe 1945–83. Basingstoke, Palgrave Macmillan.
with A. Varsori, Eds. (2010). European Union History. Themes and Debates. Palgrave, Basingstoke.
Ed. (2009). "Networks in European Union Governance". In: Journal of Public Policy. Special Issue 29(2).
with B. Leucht and M. Rasmussen, Eds. (2009). The History of the European Union. Origins of a Trans- and Supranational Polity 1950–72. Routledge, London.
with Christopher Clark Eds. (2003) Culture Wars: Secular–Catholic conflict in Nineteenth-Century Europe. Cambridge, Cambridge University Press, 2003.