British Library, national library of Great Britain, located in London; one of the world's great libraries. Long a part of the British Museum, the library collection originated in 1753 when the government purchased the Harleian Library, which belonged to Sir Robert Bruce Cotton, and groups of manuscripts. The collection grew four years later when George II donated his royal library, and was considerably enlarged with the addition of George III's library in 1823. It flourished in the 19th cent. under the leadership of Sir Anthony Panizzi. The library remained a part of the museum until 1973 when it was made a separate entity by act of Parliament. The museum complex was famous for its large, copper-domed Round Reading Room, for 140 years (1857–1997) the haunt of an array of scholars, authors, and other luminaries. In 1997 the library was moved to vast new quarters at London's King's Cross. Designed by British architect Colin St. John Wilson, the new library is spacious and multileveled, with four large reading rooms and several exhibition areas. Traditionally a nonlending reference library with manuscript and printed books divisions, the British Library now has large lending and bibliographic departments and is the copyright depository library for Great Britain and Northern Ireland. By the beginning of the 21st cent. it housed some 150 million items, including books, magazines, newspapers, manuscripts, maps, prints, drawings, musical scores, patents, various kinds of sound recordings, and stamps. The library also maintains an online catalog. Outstanding works in its collection include a unique papyrus of Aristotle, four original Magna Cartas, Beowulf, the 4th-century Greek Codex Sinaiticus Bible, a Gutenberg Bible, Froissart's Chronicles, the Lindisfarne Gospels, Leonardo da Vinci's notebooks, and the Diamond Sutra (868), probably the oldest surviving printed book.
See N. Barker, Treasures of the British Library (1988); A. E. Day, The British Library (1988) and Inside the British Library (1998).