The library houses about 170,000 works concerning the history of science. The antique book collection, consisting of nearly 5,000 works, is supplemented by several 19th-20th century collections as well as a contemporary collection which has an annual growth of hundreds of new acquisitions.
WWW Virtual Library (VL) is the oldest catalog of the Web. Unlike commercial catalogs, it is run by a loose confederation of volunteers, who compile pages of key links for particular areas in which they are expert; even though it isn't the biggest index of the Web, the VL pages are widely recognized as being amongst the highest-quality guides to particular sections of the Web.