The United States' National Science Digital Library (NSDL) is a free online library for education and research in science, technology, engineering, and mathematics. The National Science Digital Library (NSDL) Program was established by the National Science Foundation (NSF) in 2000 as a free online library which directs users to exemplary resources for science, technology, engineering, and mathematics (STEM) education and research. NSDL provides an organized point of access to STEM content that is aggregated from a variety of other digital libraries, NSF-funded projects, publishers, and NSDL-reviewed web sites. NSDL also provides access to services and tools that enhance the use of this content in a variety of contexts.
