As a social institution, libraries reflect and shape society itself. One of its fundamental roles is the preservation of information and knowledge for the library patron.

Historically, the collection of information (usually in the form of books) held for common use was what defined a library. As the growth of knowledge expanded, particularly from the 18th century and the emergence of the Enlightenment, an essential aspect of the library has been its role in the organization and classification of information to assist in its retrieval and dissemination.

Simply stated, libraries are still the most likely place where one can find specific information in an easily accessible, physical location. The social nature of libraries as institutions where like-minded individuals gather and the strong social support that libraries traditionally receive from the general public have been factors in their on-going presence in society.

In addition, libraries manifest specific social forms and purposes: National Libraries, University Libraries, Research Libraries, Government Libraries, School Libraries, Public Libraries, and Special Libraries such as Art Libraries, Music Libraries, Libraries for the Blind, etc. The increasingly specialized nature of library collections and the specialized nature of individual libraries is a reflection of the diversity of human knowledge.

Libraries are essentially democratic and the goal of a library is the improvement of society by helping the individual to understand himself or herself and the world of which he or she is a part. Libraries are managed and developed by professional librarians who are primarily service orientated but whose specific responsibilities include acquisition and collection development, bibliographic control and cataloguing, document delivery and interlibrary loans, information technology management, reference and research and circulation of material.