The aim of this master’s thesis is to examine the roles of three different public libraries in three different communities. In order to get some answers about the roles of the public libraries I have used the following questions: How is the local cultural policy formulated? How is the local library structured? What or which profiles has the public libraries in the three communities? I have made three qualitative case-studies in three different communities. These three communities are somewhat located in the same area in order to identify any cooperation between them. The communities differ in sizes so that there is a possibility to identify if the roles of the public library differ according to population. I have used an analysis model created by Marianne Andersson and Dorte Skot-Hansen as my theoretical base. The model categorises the function of the public library in four different, yet overlapping centres; as a cultural centre, as a knowledge centre, as an information centre and as a social centre. The analytical findings show that each of the three different public libraries can be identified with all four functions of the theoretical model, however in different degrees. The first library is more distinct as a cultural centre, the second library is most distinct as a knowledge centre and the third is most distinct as a social centre. The libraries have got different numbers of cooperative partners. Cooperation is viewed as important by all three libraries, mostly by the economical and inspirational contributions they provide. Cooperation also makes the libraries more visible in their respective local communities.