Engineering physics at Lehigh University, 1926-1930; graduate work in physics at University of Wisconsin, 1930-1934; Ann Arbor summer school, 1934; reputation and major interests of theoretical group at University of California at Berkeley, mid-1930s; nuclear force studies; migrations of Berkeley theorists to Caltech; major discoveries during 1930s, their communication through journals; interactions between Berkeley experimentalists and theorists in 1930s; influence of cosmic ray and astrophysics research on nuclear physics; beta decay; betatrons and synchotrons, pre- and postwar; significance of fission; contributions of war research to nuclear theory and techniques; end of war planning for higher energy accelerators; mission to Hiroshima and Nagasaki, 1945; accelerator improvements, straight sections, and phase stability, mid-1940s; effect of higher energy experiments on nuclear structure theory, postwar to early 1950s; development of the optical model after 1949; the stripping reaction; motivations for shifting into particle research in early 1950s; reactions to the revived shell model; collective model; leading centers and scientists, and major discoveries, 1945-1950; development of scattering theory and many-body theory. Also prominently mentioned are: Luis Walter Alvarez, Hans Albrecht Bethe, Niels Henrik David Bohr, Keith Allan Brueckner, Butler, Karl Kelchner Darrow, Leo Delsasso, John R. Dunning, Enrico Fermi, Herman Feshbach, William Alfred Fowler, Gerson Goldhaber, Maurice Goldhaber, Raymond George Herb, Robert Jastrow, Fritz Kalckar, Donald W. Kerst, Giulio (Cesar) Lattes, Charles Christian Lauritsen, Ernest Orlando Lawrence, Gilbert Newton Lewis, Maria Goeppert Mayer, Edwin Mattison McMillan, Benjamin R. Mottelson, J. Robert Oppenheimer, James Rainwater, Llewellyn Hilleth Thomas, Vladimir Iosifovich Veksler, Victor Frederick Weisskopf, Milton Grandison White, Eugene Paul Wigner, Robert Rathbun Wilson, Ta-You Wu, Hideki Yukawa; California Institute of Technology, Comptes Rendus, Los Alamos National Laboratory, Universit ̉di Roma, University of California at Berkeley, University of Chicago, University of Illinois, and University of Wisconsin at Madison.