a collection of books or other written or printed materials, as well as the facility in which they are housed and the institution that is responsible for their maintenance. Modern libraries may contain a wide range of materials, including manuscripts and pamphlets, posters, photographs, motion pictures, and videotapes, sound recordings, and computer databases in various forms. Modern libraries, in addition to providing patrons with access to books and other materials, often publish lists of accessions and may maintain a readers' advisory service. Interlibrary loan services, lecture series, public book reviews, and the maintenance of special juvenile collections are other important recent developments. Three systems of book classification are widely used to facilitate access to library collections: the Dewey decimal system of Melvil Dewey , the system of Charles Ammi Cutter , and the Library of Congress system (see catalog ). Since the 1930s libraries have had several technological…