William Leonard Langer (1896-1977), historian, was the Archibald Cary Coolidge Professor of History at Harvard University from 1936 to 1964 (emeritus 1964-1977). His work focused on the study of diplomacy, international politics, and foreign policy. The Papers of William Leonard Langer document the academic and professional career of Langer chiefly from 1912 to 1977.

William Leonard Langer (1896-1977), a historian, was the Archibald Cary Coolidge Professor of History at Harvard University. His work focused on modern European history, the history of international relations, and American diplomacy. The writings and publications in this collection document William Leonard Langer's academic contributions to international politics and diplomacy from the 1920s to the 1970s.