Library, collection of books, manuscripts, films, musical recordings, and other materials arranged in convenient order for use but not for sale. The earliest libraries were kept by the ancient peoples of Mesopotamia; inscribed clay tablets have been found going back to about 3500 B.C. The first public library in Greece was established in 330 B.C. The most famous library of the ancient world was begun at Alexandria, in Egypt, by Ptolemy I Soter (305–283 B.C.). The Roman Empire acquired many libraries through their conquests of Greece, Asia Minor, and Syria (1st–2nd century B.C.). During the Middle Ages the Church kept the library tradition alive in Europe. The Renaissance saw the formation of many new libraries, such as the Vatican Library (1447), the oldest public library in Europe. The growth of libraries was further stimulated by the invention of printing in the 15th century. The Bodleian Library, Oxford, England, dates from 1602. It was the 18th century that saw the formation of many of the great national libraries: the British Museum Library (1753), Italy's National Central Library at Florence (1741), and the USSR's Saltykov-Shchedrin Library in Leningrad.
The oldest library in the United States originated in 320 books bequeathed by John Harvard (1638), Harvard University's chief benefactor. The present Library of Congress developed from a purchase (1814–15) of Thomas Jefferson's personal library by Congress. One of the first tax-supported public libraries in the United States was established in New Hampshire in 1833. The American Library Association, a professional association to foster the development of the nation's libraries, was founded in 1876. An important figure in library history is Melvil Dewey, whose decimal classification system has now been adopted in many countries. In the late 19th century the industrialist Andrew Carnegie was an important benefactor of libraries. In the 20th century the public library system has been extended and consolidated and has at its disposal such technological innovations as computer data banks.