Historian, professor at the University of Warsaw and Chairman of the Academic Council for History at the university. His interests include the history of Central and Eastern Europe, particularly Czech-German relations in the 19th and 20th centuries and the political history of the Czech lands from 1918 to 1948. He has also worked on the foreign policy of the People’s Republic of Poland and forced population migrations after the Second World War.

From 2009 to 2017 he served as Deputy Director of the Museum of the Second World War in Gdańsk, co-authored the programme concept and the permanent exhibition scenario. He is a member of the editorial board of “Przegląd Historyczny” and serves on the academic boards of “Český časopis historický”, “Slovanský přehled” and “Moderní dějiny”, as well as on the academic council of the Polish Diplomatic Documents series.

He has published in “Gazeta Wyborcza”, “Newsweek”, “Polityka”, “Przegląd Polityczny” and “Tygodnik Powszechny”, among others. His major publications include: “Niemcy sudeccy 1848–1948: Historia pewnego nacjonalizmu” (Sudeten Germans 1848–1948: History of a Nationalism, 2007; Czech edition 2014), “Zmarnowana szansa?” (A Missed Opportunity? Possibilities for the Defence of Czechoslovakia in Autumn 1938, 2016; Czech edition 2018), “Kiedy wybuchnie wojna? 1938” (When Will War Break Out? 1938. A Study of the Crisis, 2019; Czech edition 2022; English and Ukrainian editions in preparation), and “Niech sobie nie myślą, że jesteśmy kolaborantami” (Let Them Not Think We Are Collaborators. The Protectorate of Bohemia and Moravia, 1939–1945, 2021; Czech edition in preparation).