- The National Library of Medicine (NLM), in Bethesda, Maryland, is a part of the National Institutes of Health, US Department of Health and Human Services (HHS). Since its founding in 1836, NLM has played a pivotal role in translating biomedical research into practice. It is the world's largest biomedical library and the developer of electronic information services that deliver trillions of bytes of data to millions of users every day. Scientists, health professionals, and the public in the US and around the globe search the Library's online information resources more than one billion times each year. The Library is open to all and has many services and resources--for scientists, health professionals, historians, and the general public. NLM has nearly 12 million books, journals, manuscripts, audiovisuals, and other forms of medical information on its shelves, making it the largest health-science library in the world.