The United States Department of Education was established in 1980 by combining several federal agencies to work towards the mission of promoting "student achievement and preparation for global competitiveness by fostering educational excellence and ensuring equal access." - Ed.gov. The department headquarters in Washington, DC is spread among several buildings. The library is located in the Lyndon Baines Johnson (LBJ) Department of Education Building on Maryland Ave.
Although the library is in the basement of the building, the space has a picture window across from the reference desk that looks out onto a green space, which lets in natural light. The National Library of Education (NLE) collection contains over 60,000 books and more than 1000 English language electronic and print journals with a central focus on education, but also includes related subject areas such as "law, public policy, economics, urban affairs, sociology, history, philosophy, psychology, and information science" - NLE. The library is administered under the The National Center for Education Evaluation (NCEE), which is tasked with evaluating federal programs and disseminating information, among other things. The NCEE also oversees the Education Resources Information Center (ERIC) which is the world's largest digital library of grey literature on education such as conference, research, or policy reports and papers. ERIC was developed to provide an easy to use and search widely accessible database of bibliographic and full-text education research and information. While, commercial vendors may offer more extensive access to full text databases, ERIC is still a very useful resource for research into this subject area.
The NLE is open to the public for on-site access to collections, as well as services by phone, web, fax and mail. Services include statistical and reference services, government documents access as a Federal Depository Library and access to some material through inter-library loan. The library catalog is available online for search, although many of the electronic resource links are restricted and require on-site access or ILL request through your local public, school or academic library.
One question I came across through a visit to Library of Congress was posed by a researcher there. I attended a tour of the Business Resources Reading Room. We were discussing the collection development policy of the LOC and an attendee asked if any library keeps a historical archive of textbooks used in public schools, if someone were researching what was taught in the past and how it has changed. I thought it was an interesting question. Library of Congress doesn't generally collect textbooks, which is explained in the education section of the collection development policy. The librarian did say they sometimes receive reference questions from students looking for the teacher's guide with answers to tests.
In case you are now wondering, there doesn't appear to be a definitive collection of historical textbooks. I conducted a very quick and in no way exhaustive search for libraries with textbook collections. Library of Congress has a special collection of McGuffey Reader Collection. Indiana University of Pennsylvania has a collection development policy for textbooks, to support the College of Education and Educational Technology, but only keeps current editions. The University of Chicago Library has a subject guide pointing to a few more collections of historical textbooks. Other resources include The Center for Research Libraries, Nietz 19th Century Schoolbooks, or the Harvard Graduate School of Education special collection of historical textbooks.
You can add National Library of Education to the list. Their collection of textbooks is organized by subject and contains textbooks for the mid 1800s to the mid 20th century. The library’s collection also includes most of the reports by the Department and its predecessors going back to the 1870’s as well as a collection of federal education legislation. This library is yet another example of fascinating special collections where the ability to focus collection to a specific subject area allows the collection to dig deep for information available with a narrow scope. If you have the opportunity to visit, check out the school bus collection at the entrance. It's pretty adorable.