Begun in the early 1800s as a part of the Office of the Surgeon General of the Army, NLM has expanded its mission and scope to become one of the country's three national libraries¹ and the primary collector of medical information (Miles, 1982). NLM's collection exceeds 5 million books, journals, and audiovisuals on health and medicine. The library also provides access to more than 40 online databases through its Medical Literature Analysis and Retrieval System (MEDLARS) (NLM, 1995). One of NLM's most well-known achievements is the bibliographic database MEDLINE, which is internationally respected as a source of citations and abstracts to the world's medical literature. Approximately 300,000 citations are added to the MEDLINE database annually.

The Lister Hill National Center for Biomedical Communications and the National Center for Biotechnology Information are the research and development arms of NLM. Through these centers, NLM conducts a range of intramural and extramural research to explore new technologies in the fields of medicine, library science, computer science, and informatics.

The National Library of Medicine Act of 1956 (Public Law 84-941) broadly mandated that NLM collect and organize health sciences information "to assist the advancement of medical and related sciences, and to aid the dissemination and exchange of scientific and other information important to the progress of medicine and to public health" (NLM, 1986). The library works with the 4,500 health science libraries of the National Network of Libraries of Medicine (NN/LM) and the eight Regional Medical Libraries (covering all geographic regions of the United States) to provide health professionals and other interested individuals with access to biomedical information. More than 3 million interlibrary loan requests are filled annually by NN/LM.

NLM is organized into six divisions (Figure 2.1), the largest of which is Library Operations, responsible for fundamental library services including literature collection, indexing, and cataloging. In fiscal year (FY) 1995, NLM employed 586 full-time equivalent (FTE) personnel.