The National Library of Medicine originated as a few books in the office of the army's surgeon general, Joseph Lovell, between 1818 and 1836. It became the nation's largest medical library after the Civil War under the direction of John Shaw Billings and began publishing the Index-Catalogue of the Library of the Surgeon General's Office and preparing the Index Medicus. After Billings retired in 1895, the library marked time as army medical officers were rotated through as directors until modernization began under Harold Wellington Jones during World War II. during the directorship of Frank B. Rogers (1949-1963), who introduced MEDLARS, guided the move to a new building in Bethesda, and revitalized other operations, the institution received statutory authority as the National Library of Medicine within the Public Health Service (1956). By 1965, which was marked by the passage of the Medical Library Assistance Act, the library had again regained a position of world leadership.