Early life and education; research on spectroscopy with Robert A. Millikan at University of Chicago and Caltech; early teaching career at Caltech; work on forbidden lines, 200-inch telescope project; visitors to Caltech during the 1930s include Albert Einstein and Arnold Sommerfeld; effects of the Depression and World War II on astronomy; postwar reorganization, staff and funding at Mt. Wilson and Palomar Observatories; Edwin P.