Childhood in New York; high school experience at Horace Mann; Harvard undergraduate at the age of 15. Impressions of ordeal with Harlow Shapley. Depression years in the family business, return to a very changed Harvard in 1934. Thesis work on Interstellar Absorption (Bart Bok), Ph.D. 1937. Postdoc at Yerkes Observatory (Otto Struve) working on Upsilon Sagittarius. Develops the 140-degree camera (the Greenstein-Louis G. Henyey camera); work with Fred Whipple on radio signals from space (Karl Jansky, Grote Reber), Greenstein and Reber’s review article on classified radio detection work during World War II. Founding of the Astrophysics Department at Caltech. Radio astronomy in the mid-1950s. Work on white dwarfs from 1957 on. Own accomplishments as scientist and in personal life. Impressions of Martin Schwarzschild, Shapley, Reber, Fred Hoyle. Also prominently mentioned are: Walter Sydney Adams, Lloyd Viel Berkner, John Bolton, Leverett Davis, William Alfred Fowler, Leo Goldberg, Louis Henyey, Fred Hoyle, Edwin Powell Hubble, Milton Lasell Humason, Robert Hutchins, Karl Jansky, Gerard Peter Kuiper, Tom R. Matthews, Robert Reynolds McMath, Donald Howard Menzel, Paul Merrill, Rudolph Leo Bernhard Minkowski, William Wilson Morgan, Guido Munch, Beverly Oke, Donald Osterbrock, Cecilia Payne-Gaposchkin, Harry Hemley Plaskett, Robert Richardson, Allan Sandage, Jan Scheldt, Shklovsky, Charlotte Moore Sitterly, Lyman Spitzer, Edward Teller, Richard Chace Tolman, Robert Julius Trumpler, Merle Antony Tuve, Albrecht Otto Johannes Unsold, Immanuel Velikofsky, Frederick Whipple; Carnegie Institution of Washington, Hale Observatories, Harvard College Observatory, Lick Observatory, McDonald Observatory, McDonald Observatory Nebular spectrograph, National Science Foundation (U.S.), 100-inch Telescope, University of Chicago, and Vista Project.