With its collection of more than 330,000 media items, the library of the Leibniz Institute for East and Southeast European Studies ranks internationally among the largest libraries of its kind in the humanities and social sciences. Collecting and making available literature on Eastern Europe (catalog), it exists to support research conducted at the Institute and by the (inter)national academic community. It performs this task by lending literature internally, locally and transregionally (interlibrary loans). In addition, by means of its own projects and in cooperation with the Institute's other divisions and external partners, the library contributes i to the creation of an electronic research environment for research into East and Southeast Europe. The library is actively involved in the digital information opportunities provided by the Virtuelle Fachbibliothek Osteuropa (Virtual Library Eastern Europe – ViFaOst), the IREON gateway and the document server for East European studies, Ostdok, all of which have been funded by the German Research Foundation. The services offered by the library are oriented towards the requirements of the Institute's staff and guests.
The library collection facilitates studies not only on individual countries but also on the entire regions of East and Southeast Europe. This broadly conceptualized collection opens up comparative research perspectives on economics, politics, society and culture in the past and present. The collection contains essential literature on both the region's imperial aspects and its transformational processes. Enhanced by a very high proportion of literature that is unique to the IOS, both in Germany and, to some extent, the world, the library offers an environment of unparalleled excellence for historical and social science studies on all the countries of East and Southeast Europe. The extensive stock of maps, statistics, historical newspapers and journals, books of statute, school programs and literature on migration and minorities in Eastern Europe represents a collection of outstanding importance.
The reading room houses around 600 titles of current journals as well as 5,000 general and geographical reference works, dictionaries and compendiums for instant access. Literature from the library's closed stacks may be ordered and will be brought immediately to visitors in the reading room. Institute staff and guest scholars may take borrowed items to their workplaces. Other users may borrow literature over the weekend. The in-depth classification of the stock's content enables comprehensive research and provides an outstanding service to users that makes the library catalog especially valuable.