The Münchner Musikbibliothek (Munich Music Library) was founded by the musical journalist Paul Marsop (1856–1925) in 1902. It opened to the public in 1905. Marsop was inspired by the idea to educate the people and to enable all levels of the population to gain access to good music. Therefore, he provided his private musical collection as well as substantial financial means to implement his plan of a "Musikalische Volksbibliothek" (musical people's library). The Münchner Musikbibliothek thus became the first of over 30 musical people's libraries Marsop was going to found during the following years in Europe.
In 1907, the library became a donation to the Munich magistrate. Subsequently, in 1925/26, the then director of the Stadtbibliothek (municipal library), Hans Ludwig Held (1885–1954), reorganised it and incorporated it into the association of municipal libraries. By 1929, the library had grown to an inventory of 28,000 volumes and moved to larger premises on Salvatorplatz. In 1935, a soundproof music room with a concert grand piano was installed there. Two years later record archives were set up together with facilities for playing them. Thanks to the spirited intervention of the librarians, in 1936 sheet music of ostracised composers could be saved from destruction by the Nazi regime. In 1946 Dr. Alfons Ott (1914–1976) became director. He divided the library into part loan library and part scholarly reference library. In 1984, the move into the newly constructed Kulturzentrum Gasteig (Cultural Centre Gasteig) took place. As a result, the Münchner Musikbibliothek was now physically incorporated into the Münchner Stadtbibliothek.
The Musikbibliothek of the Münchner Stadtbibliothek is the largest municipal music library in Germany. Its inventory combines important autograph manuscripts with rare prints (rara) as well as with numerous bequests by Munich and Bavarian composers. It also includes popularised music literature, sheet music for gaining practical experience and a substantial collection of sound recording media. Easy-access musical offers for non-professional music lovers, the support of schoolchildren and students as well as the provision of a broad range of literature for professional musicians form part of the tasks performed by the Musikbibliothek and so is the supply of a scientific reference library for the purpose of academic research and teaching.
Based on Paul Marsop's private library consisting of 2,000 exemplars of sheet music and books, which he had made available as basis, the collection grew to a present inventory of c.250,000 media thanks to a busy activity of collecting and acquisition as well as to the numerous donations and bequests. Manuscripts by Johannes Brahms, Richard Strauss and Max Reger belong to the collection's showpieces. 80 bequests by musicians and composers such as Hans Knappertsbusch, Mark Lothar, Anton Beer-Walbrunn and Kurt Brüggemann as well as special collections, for example the Volksliedarchiv König (Folksong Archive König) and the Gitarristisches Archiv (Guitarist Archive), found their homes in the Musikbibliothek. At first limited to classical music, from 1961, jazz and popular music became part of the collections.