[3] 10 000 old prints are referenced: Currently collection includes 97 incunables (issued before 1500),[4] the following ones being the most precious:[3] Other important volumes:[5] Since 1936, Bernardine library manuscripts are exhibited in the "Royal Hall" and the "Bernardyńska ward" designed by Wiktor Zabielski and Jerzy Rupniewski, with stained glass by Edwarda Kwiatkowski.

Origins of the actual institution date back to the creation of the Bernardine library in 1488, which stood at the location of today's Church of Our Lady Queen of Peace.

The monastery had organised manuscripts into several disciplines: In addition, the library had books dealing with law, geography, mathematics, astronomy, medical science, mining and metallurgy.

Most of the books come from purchase or donations, some have been brought by monks travelling abroad (Dionizy Szyjka, Jan of Kościan, Melchior Dębiński, Wawrzyniec of Słupca and others).

In 1631, Jan Synodoniusz of Pakość, dying chaplain of the Church of the Holy cross in Bydgoszcz (now gone), bequeathed to the library a sizable collection of books.

One of the famous professor of the philosophy was Bartłomiej of Bydgoszcz, a bernardine monk who conducted fruitful scholarship work at the local monastery, issuing the first Latin-polish dictionary in 1532.

Witold Bełza, the new director, (1920-1939 and 1945-1952), began to acquire more Polish books, and in 1939 the stock increased to 150 000 volumes, including: During interwar period, the collections of the Municipal Library in Bydgoszcz were regarded as the richest on Kujawy in terms of literature.

Some of the books were hidden in the Municipal museum or in basements of elementary schools in the suburbs of Bydgoszcz, so as not to be evacuated by German occupation forces.

It included among others, 1382 volumes from the Bernardine library, 4 900 items related to cartography, 972 manuscripts of artists such as Józef Ignacy Kraszewski, Maria Konopnicka, Julian Krzyżanowski, Jan Matejko, Henryk Sienkiewicz, Adam Grzymała-Siedlecki, Leopold Staff, Stanisław Wyspiański and Tadeusz Boy-Żeleński.

[11] From the 1950s to the 1970s, the municipal library established many branches throughout the city: a new building has been planned to be erected, but the project was finally rejected and transformed to a major overhaul of the existing edifice.

[9] In 2009, a plaque in memory of Józef Wybicki, a Polish jurist, political and military activist, has been unveiled on a wall of the Municipal Library, recalling its judicial past.

[16] Between both library buildings runs the narrow Zaułek street: to unite the architectural ensemble, a covered passage called the "Bridge of Sighs" (Polish: Most Westchnień), has been built in 1920.

The outbuilding on the first floor harbours a collection of antique books from the ancient Bernardine monastery library,[15] which stood in the 16th century in Bernardyńska Street.

[17] Its creator was sculptor Karol Kowalczewski, and the funder Alfred Kupffender, owner of the pharmacy "Under the Golden Eagle" (Polish: Pod Złotym Orłem), located on Stary Rynek.

[20] After the end of World War II, a newly cast "The Well", has been unveiled on May 1, 1948, moving its original location to stand right before the main elevation of the Municipal Public Library on Stary Rynek.