This collection consists of material related to Bernhard Witkop's professional and personal relationship with the famed African American chemist, Percy Lavon Julian, primarily in the form of correspondence. Witkop also served as a personal assistant to the Nobel Prize-winning chemist Heinrich Wieland from 1938-1946. Witkop, a German native and Jewish on his mother's side, credits Wieland for his shelter from the Nazis during World War II. Witkop's recollections of Wieland are included in the collection. Only a small portion of the collection has been digitized.