Library of Congress
The Library of Congress is the nation's oldest federal cultural institution and serves as the research arm of Congress. It is also the largest library in the world, with millions of books, recordings, photographs, maps and manuscripts in its collections.
catalogs | digital collections | website
National Library of Medicine
The National Library of Medicine (NLM), on the campus of the National Institutes of Health in Bethesda, Maryland, is the world's largest medical library. The Library collects materials and provides information and research services in all areas of biomedicine and health care.
catalog | digital collections | website