Langer, William Leonard
William Leonard Langer, 1896–1977, American historian, b. Boston. He received his Ph.D. from Harvard in 1923 and began teaching there in 1927. Langer served in U.S. intelligence in World War II and as assistant to the Secretary of State in 1946. A leading authority in the field of diplomatic history, he wrote extensively on the diplomatic climate preceding World Wars I and II. His many works include The Diplomacy of Imperialism (1935, 2d ed. 1951), European Alliances and Alignments (1939, 2d ed. 1950), Our Vichy Gamble (1947), and, with S. E. Gleason, The Challenge to Isolation, 1937–40 (1952) and The Undeclared War, 1940–41 (1953). Langer also edited An Encyclopedia of World History (5th ed. 1972) and the valuable series The Rise of Modern Europe (1934–74), an analytic synthesis. He was one of the first to urge that historians make fuller use of related disciplines, especially of psychology.