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. Hubble's role at the observatory; educational aspects of the observatory program (professional and public); research groups and research interests; theorists and observationalists, Jesse Greenstein, Guido M nch, Jan Oort, radio astronomy; recollections and evaluations of own work after retirement. Also prominently mentioned are: Walter Sydney Adams, Harold Delos Babcock, William Alvin Baum, Wilhelm Bjerknes, T. Bowen, Geoffrey R. Burbidge, Margaret Burbidge, Vannevar Bush, J. Carroll, Lee Alvin DuBridge, Theodore Dunham Jr., Edlň, Robley Dunglison Evans, William Alfred Fowler, Henry Gordon Gale, Cecilia Helena Payne Gaposchkin, George Ellery Hale, John L. Hall, Don Hendrix, Alfred H. Joy, Thomas Lauritsen, Ernest Orlando Lawrence, Max Mason, Edwin Mattison McMillan, Merriam, Paul Merrill, Rudolph Leo Bernhard Minkowski, R. Otis, Henry Norris Russell, John Donovan Strong, Richard Chase Tolman, Merle Antony Tuve; Carnegie Corporation of New York, Carnegie Institution of Washington.