Jagiellonian Library (Polish: Biblioteka Jagiellońska, popular nickname Jagiellonka) is the library of the Jagiellonian University in Kraków and with almost 6.7 million volumes, one of the biggest libraries in Poland, serving as a public library, university library and part of the Polish national library system. It has a large collection of medieval manuscripts, for example Copernicus' De Revolutionibus or Jan Długosz's Banderia Prutenorum, and a large collection of underground literature (so-called drugi obieg or samizdat) from the period of communist rule in Poland (1945-1989).