The UCLA Library Special Collections houses and provides access to the UCLA Library's central collection of rare books and manuscripts in the humanities and social sciences. Its rare book holdings consist of some 333,000 volumes, while its non-book holdings comprise more than 30 million manuscripts, 5 million photographs and negatives, ephemera, maps, works of art, architectural drawings and models, and other graphic arts material. The Department has five divisions: Manuscripts, Rare Books, Technical Services, Public Services, and University Archives. As one of the 23 public service units and departments with the UCLA Library system, the Department's resources support the University's research and teaching missions. The UCLA Library's collections as a whole are open to the general public for reference and research, and about one-third of the Department's current users are from outside the university community.