The article deals with socio-cultural institutions - museum and library, which are important cultural phenomena, reveals their interpenetration and interaction. The  author points out the value of the book as a signifiant element of the literary culture, an effective mechanism of social memory, the major phenomenon of the library. Building on the culturological analysis the paper describes the museum libraries in the city of Belgorod: their activities, signifiance, and role, as well as the problematic aspects and characteristic features. The range of museum services has been lately extended, but the museum library remains in the shadows, being mostly accessible only to a museum staff. The museum library often does not have duplicate copies, which makes it even more signifiant, capable of preserving the intellectual, cultural heritage; it often does not provide reading rooms, which somewhat complicates the use of its funds. The article points out that the state fiancial support of the library potential of the museum is needed, which will contribute to the accumulation and preservation of national spiritual and material values of the society. Information support of the museum and the museum library is also important on various network resources and in various educational institutions. The article concludes that the museum library has great cultural potential, is an important component of the museum, it is a unique phenomenon, the keeper of the national cultural heritage. By opening access to its libraries, the museum could replenish its target audience, as well as contribute to the formation of a book culture that is becoming more multi-dimensional. Therefore, it is necessary to create conditions opening the access to the collections of museum libraries.