Library of Congress, Jefferson building

The Library of Congress is one of four official national libraries of the United States (along with the National Library of Medicine, National Agricultural Library, and National Archives and Records Administration). Originally founded as a research library for the U.S. Congress on April 24, 1800, its original collection was composed of the books of former U.S. President Thomas Jefferson. Later, the Library assumed a role as a legal repository to guarantee copyright protection. All authors seeking American copyright had to submit two copies of the work to the Library. This requirement is no longer enforced, but copies of many books published in the U.S. still arrive at the Library regularly. It contains many important books and collections, such as a Gutenberg Bible.

The Library itself is spread over three buildings in Washington, D.C.:

• The James Madison Building (between First and Second Streets on Independence Avenue SE)
• The Thomas Jefferson Building (between Independence Avenue and East Capitol Street on First Street SE)
• The John Adams Building (between Independence Avenue and East Capitol Street on 2nd Street SE)

Main Library of Congress Building at the start of the 20th century

The Library also developed a system of book classification called Library of Congress classification (LC) which is used by most research and university libraries, although most public libraries continue to use the Dewey decimal system.

With over 128 million items, it is one of the largest libraries in the history of the world, surpassed only by the British Library, which contains over 150 million items. With over 520 miles of shelves, the Library of Congress certainly is the longest library in the world.

The library is open to the general public for academic research, and runs tours for visitors. Only people with a permit can enter the reading room and access the collection. Permits are available in the Madison building upon presentation of a picture ID.

It is estimated that the print holdings of the Library of Congress would, if digitized and stored as plain text, constitute 17 to 20 terabytes of information. This leads to the commonly-repeated but misleading equivalence of 20 terabytes to the entire holdings of the Library. Only selected portions of the print holdings have actually been digitized, and the Library currently has no plans for systematic digitization of any significant portion of its books. The Library makes millions of digital objects, comprising tens of terabytes, available at its American Memory site. American Memory is a source for public domain image resources, as well as audio, video, and archived Web content. Nearly all of the lists of holdings, the catalogs of the library, can be consulted directly on its web site. Librarians all over the world consult these catalogs, through the Web or through other media better suited to their needs, when they need to catalog for their collection a book published in the United States. They use the Library of Congress Control Number to make sure of the exact identity of the book.

Library of Congress reading room

The Library of Congress also provides an on-line archive of the proceedings of the U.S. Congress at Thomas (http://thomas.loc.gov), including bill text, Congressional Record text, bill summary and status, the Congressional Record Index, and the United States Constitution.

Librarians of Congress

The head of the Library of Congress is called the Librarian of Congress. The list of past Librarians of Congress includes several notable figures:

• John J. Beckley (1802–1807)
• Patrick Magruder (1807–1815)
• George Watterston (1815–1829)
• John Silva Meehan (1829–1861)
• John G. Stephenson (1861–1864)
• Ainsworth Rand Spofford (1864–1897)
• John Russell Young (1897–1899)
• Herbert Putnam (1899–1939)
• Archibald MacLeish (1939–1944)
• Luther H. Evans (1945–1953)
• L. Quincy Mumford (1954–1974)
• Daniel J. Boorstin (1975–1987)
• James H. Billington (1987–)

See also

• Library of Congress Country Studies
• Congressional Research Service
• Poet Laureate Consultant in Poetry to the Library of Congress
• Library of Congress Living Legend
• Library of Congress Classification

External links

• The Library of Congress website (http://www.loc.gov/)
• History of the Library of Congress (http://www.loc.gov/loc/legacy/)
• American Memory (http://memory.loc.gov/)
• thomas.loc.gov, legislative information