Collection documents his work in cosmic rays in academic, governmental, and international settings, and provides insight into the field of physics in the 20th century. Significant topics include neutrons and optical dispersion; development and use of devices for measuring radiation; radiocarbon dating; physics research and its social and political context, expecially in South America; international scientific cooperation and the International Geophysical Year; eclipses; high altitude balloon flights; and government and military funding of scientific research. Correspondents include leading American, South American and European physicists, academicians from other disciplines, professional scientific organizations, government agencies, military personnel, and publishing concerns. Korff's notes deminstrate his research methods, details of his experimental data and his prose style. Also included in the collection are information on research projects and expeditions; grant proposals and reports; materials on scientific conferences; students' theses and dissertations; administrative records pertaining to NYU and its physics department; and reprints of scholarly articles by Korff and others.