The branch library, Deák Ferenc Library operates in Rottenbiller Street 10. This institute became a special venue of cultural opposition in the mid-1970s. Two librarians, Péter Hont and Károly Kály-Kullai, established the first semi-legal Hungarian popular music collection here.

The predecessor of the library was founded by the Deák Ferenc Masonic lodge in 1913 on Almássy Square. This was the first public library in Budapest. Because of lack of storage space, the institution was moved to Rottenbiller Street in the 1950s. According to Kály-Kullai, given its origins, the library had both a legendary and independent identity within the municipal library network. The library was closed between 1982 and 1986 because of renovation work. When it reopened, the pop music collection already existed.