Skip to main content

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.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Langer, William Leonard." The Columbia Encyclopedia, 6th ed.. . 22 Apr. 2019 <>.

"Langer, William Leonard." The Columbia Encyclopedia, 6th ed.. . (April 22, 2019).

"Langer, William Leonard." The Columbia Encyclopedia, 6th ed.. . Retrieved April 22, 2019 from

Learn more about citation styles

Citation styles gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, cannot guarantee each citation it generates. Therefore, it’s best to use citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

The Chicago Manual of Style

American Psychological Association

  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.