Wydawnictwo Naukowe PWN (Polish Scientific Publishers PWN; until 1991 Państwowe Wydawnictwo Naukowe - National Scientific Publishers PWN, PWN) is a Polishbook publisher, founded in 1951. The printing house is best known as a publisher of encyclopedias, dictionaries and university handbooks. It is the leading Polish provider of scientific, educational and professional literature as well as works of reference. It authored the Wielka Encyklopedia Powszechna PWN, the largest Polish encyclopedia. New version of the PWN Encyclopedia, published since 2001, is Wielka Encyklopedia PWN. All its volumes should be published by the end of 2005. There is also online PWN encyclopedia – Internetowa encyklopedia PWN.