The library collects books, journals, electronic and audiovisual publications published in the territory of Poland. It also collects materials related with polish culture published abroad. It is the most important humanities research library. It is also the main archive of Polish writing and the state centre of bibliographic information about books. The role of gathered collections is great in case of any scientific activity. It is an important methodological center for other Polish libraries. Copy of every book published in Poland is placed in this library.