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Verner W. Clapp started as a Summer Clerk in the Library of Congress in 1914. He quickly rose through the ranks, becoming Chief Assistant Librarian in 1929 and Librarian of Congress in 1939. He served as Librarian until 1953, when he retired. Clapp was a major force in the modernization of the Library of Congress, and he is credited with helping to establish the Library as a leading research institution.