The purpose of this Master’s thesis is to describe and analyse the development of the public and the study circle libraries in the district of Kolbäck during the period of 1913-1954. The factors important for the library development described in sub-questions are: financing, locality, staffing, stock of books, book-lending level and uniting district effects. I use a hermeneutic interpretation model of interaction between the parts and the wholes, between reasons and results. This research leans mainly upon material which is sent to be deposited in archives in Hallstahammar, Västerås and Grängesberg. The public library in Kolbäck was established in 1914 as a reconstruction of an older facility. The first study circle library was opened the year before. In the following years four branches and six study circle libraries were established. Those last mentioned belonged to Arbetarnas bildningsförbund (ABF), Godtemplarorden (IOGT), Nationaltemplarorden (NTO), Sveriges kristna bildningsförbund (SKB) later Sveriges kristna studieförbund (SKS) and Svenska landsbygdens studieförbund (SLS). In 1943 two branches were handed over to Hallstahammar due to changes in community boarders. After 1952 four branches were added from Rytterne and Säby, but there were also opened two new book lending stations. The economic conditions changed in the late forties that set in favour the public libraries. As a result many of study circle libraries were closed down and their book collections were handed over to the local public library. This was a development which was at the time encouraged by the Swedish state. Through the whole period there were only part-time librarians employed in Kolbäck.