The Martin Opitz Library is the central library for German culture and history in Eastern Europe. It collects literature from all areas of East-Central, Eastern and South-Eastern Europe. The main focus of the collections is on the regions that today form western Poland and the Kaliningrad region – the historical East Germany. With more than 350,000 volumes, the Martin Opitz Library is the largest specialist library in this field in Germany.
The Martin Opitz Library collects written records on the history and culture of the Germans in the entire area of Eastern Europe. One focus of the collection is the historical Prussian eastern provinces (Silesia, Pomerania, East and West Prussia, East Brandenburg). In addition, the library has extensive holdings on all areas in South and North-East Europe where Germans lived alongside other nationalities.

Thematically, the library mainly collects historical works, especially historical regional studies, local and family histories as well as church and religious histories. In addition to this is the so-called “Schöne Literatur deutschsprachiger Autoren” (beautiful literature of German-speaking authors) from the above-mentioned regions, including relevant German literary research. A further focus of the collection is migration and minority research, dealing with the flight, expulsion and integration of German expellees as well as the integration of immigrants. In addition, the Martin Opitz Library collects literature from numerous other fields of knowledge.