This series contains materials that shed light upon Oppler's personal and professional life. Included are a photocopy of a book of poems authored by Oppler's father Leo, photographs, and photocopies of his published obituaries. Also included are a handful of materials documenting his daughter Ellen's career as an art historian.
This series contains published and unpublished writings, research and lecture notes, and research materials generated or collected while Oppler was a research assistant (1940-44) and instructor at the School for Overseas Administration (1941-44).
This subseries contains typescript and published articles, essays, and lecture notes. Of note are correspondence with social scientist Ernst Fraenkel, a ca. 1941 autobiographical essay entitled "Mein Leben in Deutschland vor und nach dem 30. December 1933", typescript and published versions of "Ethics in Public Administration and Individual Ethics", and "Prussian Bureaucracy and National Socialism", a lengthy and unpublished analysis of the Prussian civil service in Imperial, Weimar, and Nazi Germany.