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, by then the largest Polish encyclopedia, as well as its successor, the Wielka Encyklopedia PWN, which was published between 2001 and 2005. There is also an online PWN encyclopedia – Internetowa encyklopedia PWN.