Life of his father, Karl Schwarzschild; father's scientific relationships in Göttingen (Felix Klein, David Hilbert); move to Potsdam, 1909; relations with Potsdam and Berlin scientists (Albert Einstein, Karl Sommerfeld); father's Jewish background concealed. M. Schwarzschild's youth in Göttingen and Berlin; early education, interest in astronomy and mathematics. Undergraduate at Göttingen Universität (Hans Kienle, Richard Courant, Neugebauer), 1930-1933; graduate work at Gottingen Observatory, 1933-1935; his reaction to Nazism. Introduction to astrophysics (Arthur Eddington), interest in stellar interiors and stellar evolution; contacts with other astronomers from Gottingen Observatory (Otto Heckmann, Kienle, Rupert Wildt); comments on general relativity; interest in pulsating stars; leaves Göttingen, 1936. Postdoctorate at Oslo (Svein Rosseland); Jan Oort, Ejnar Hertzsprung; mechanical analog computer for computations in astrophysics and celestial mechanics; comments on development of theory of stellar interiors, 1939-1950. To Harvard College Observatory (Harlow Shapley), 1938; C. Payne-Gaposchkin, Bart Bok; comparison of European and American observational style, social scene; Barbara Schwarzschild's difficulties as female astronomer; contacts with S. Chandrasekhar and other astronomers. Tour of the United States; visits Mt. Wilson Observatory (Wilhelm Baade, Rudolph Minkowski, Edwin Hubble, Milton Humason), 1940; Shapley's relationship with Mt. Wilson staff. Harvard (Fred Whipple), 1938-1941; Shapley as a leader; astronomy summer school at Harvard; work on Cepheid variables in M3 (Bok, Chandrasekhar); overall impact on Schwarzschild of Harvard period. Columbia University (Jan Schildt, I. I. Rabi), 1940-1942; difficulties there; origin and funding of Thomas Watson Astronomical Computing Center; discussion of cosmology in the late 1930s; contacts with physicists (Enrico Fermi). In U.S. Army, 1941-1945; enters as private, teaches math to recruits; refuses invitation to Los Alamos; transferred to Aberdeen Proving Ground, dissatisfaction there; to officers training school, does bombing analysis for Italian campaign. Work relating to stellar interiors and evolution, 1938-1946; nuclear energy source ideas (Hans Bethe, Fermi); Eddington, Gerard Kuiper, Chandrasekhar, G. Keller; German astronomers during World War II (Ludwig Biermann). Discussion of wife's career and her role in his career. Early ideas about red giants (Öpik, Herman Bondi, Fred Hoyle), 1946-1950. Work on acoustic wave energy transport (R. Richardson, Gold); work on chemical composition differences in stellar populations. To Princeton University (Spitzer, H. N. Russell), 1947; Project Matterhorn (start of bomb and fusion projects); relationship with Russell. Stellar evolution work in the 1950s; computer work (John Von Neumann, Richard Härm), mid-1950s; collaboration with Allan Sandage evolving a stellar model, 1952; computing towards red giants; observational cluster work, 1951; ages, metallicity, and the Big Bang; beginnings of "astrophysical" cosmology. Evolution theory after late 1950s; effect of computers on theoretical progress; relation of evolution theory to cosmology; general comments on his work in stellar evolution; interactions with Robert Dicke; views on cosmology, general relativity. Need for better solar convection work leads to use of balloons (James Van Allen); post-Sputnik funding; on cooperation with industry and engineers; Stratoscope II (Bob Danielson, Spitzer). Years advising the National Science Foundation, President's Science Advisory Committee, 1959-1976, and National Aeronautics and Space Administration (Von Neumann), to 1969; The International Astronomical Union, 1964-1970; American Asronomical Society, 1967-1973. Informal advisor to various observatories: Kitt Peak National Observatory, Mt. Wilson-Palomar Observatories, Carnegie Southern Observatory. Recent work on galactic structure. Reflects on importance of ethical standards; his feelings about religion and nature.