Description: Papers of Louis Julius Koester Jr. (1925-85), professor of physics (1955-85) including correspondence (1956-84), publications (1951-85), research files in high energy nuclear physics including the helium 3 nucleus (1953-84), conference material (1957-84), course materials on optics (1962-80), Physics 170 (photography), 321-2 (theoretical mechanics), committee files (1957-84) and 342 (electricity & magnetism), 343 (electronic circuits) & laboratory notebooks (1960-80).