The Vatican Apostolic Library (Latin: Bibliotheca Apostolica Vaticana), more commonly called the Vatican Library or simply the Vat,1 is the library of the Holy See, located in Vatican City. Formally established in 1475, though in fact much older, it is one of the oldest libraries in the world and contains one of the most significant collections of historical texts. It currently has 75,000 codices from throughout history,2 as well as 1.1 million printed books, which include some 8,500 incunabula.
Wikipedia article: https://en.wikipedia.org/wiki/Vatican_Library
The Vatican Library is separate institution from the Vatican Secret Archives.