The Library of Congress is the depository of all written material copyrighted in the United States. Established in 1800 with a few thousand books, it is now the world's largest library with some 530 miles of bookshelves housing more than 130 million items, including printed materials, photographs, manuscripts, maps and recordings.

The library used to be housed in the Capitol until the building was burned by British troops in 1814. It later moved to permanent quarters in 1897. The major step in rebuilding the collection was taken in 1815, when Congress purchased the 6,000-volume personal library of Thomas Jefferson. In 1930, it became the largest collection of incunabula in the Western Hemisphere after the purchase of the books of Dr. Otto H.F. Vollbehr. The main Library of Congress building was erected in 1897; the library also occupies the Thomas Jefferson building, formerly called the annex, and the new James Madison building.

Though originally built in order to serve as a reference source for members of Congress and other government officers, the Library of Congress grew into the largest and one of the greatest among the learned institutions of the world. Its impressive collection includes 18 million books, 2.5 million recordings, 12 million photographs, 4.5 million maps, and more than 54 million manuscripts. Because of its copyright function, it receives a copy of every book copyrighted in the United States. The American Folklife Center, administered by the library, collects and preserves American folklore; it supports research projects and presents performances and exhibitions of folk music, arts, and crafts.

The post of Librarian of Congress is appointed by the president with the advice and consent of the Senate. The position often goes to eminent scholars and artists, as well as to professional librarians. Recent Librarians of Congress include Archibald MacLeish (1939-44), L. Quincy Mumford (1954-74), Daniel J. Boorstin (1974-87), and James H. Billington, who is the thirteenth Librarian of Congress and was appointed by Ronald Reagan in 1987.