The National and University Library in Zagreb is the central library in the Republic of Croatia and also the fundamental institution of Croatian culture, science and education. It was founded in 1607 as a collegium but officially started to gain national importance with the introduction of legal deposit regulations (1816 and 1837). In 1837, Antun Kukuljević gave the National and University Library a Latin name, Nationalis Academica Bibliotheca, highlighting its dual functions. During the 19th and 20 centuries, the National and University Library was enriched through many book donations, and the estimation is that it holds approximately 3 million books. 

It was originally located in an abandoned Dominican monastery in today’s Trg Svete Katerine 5, and later in the building of the current Rector’s Office, located at today's Croatian State Archives, and since 1995 has been located in an impressive and newly constructed building in a street called Ulica Hrvatske bratske zajednice.

Its primary function is to store Croatian cultural property in written, printed, and modern digital form. This task was carried out in its entirety even during the period of socialism which is particularly evident in the fact that the so-called unsuitable books were also kept. During that period, the institution itself had no opposition role; it was the official, central Croatian library. However, there did exist opposition activity amongst some of its employees, for example, Branko Hanž who stored away the unsuitable books.