Early career through 1939. Midwestern background; education at University of Texas, graduate work at Harvard University in theoretical physics under Edwin C. Kemble and John Van Vleck, 1929-1933; traveling fellowship (chiefly in Germany, 1932); positions at Harvard, University of Wisconsin, Princeton University, and New York University. The nature of theoretical nuclear physics work in the 1930s including nuclear models and Feenberg's work with Eugene P. Wigner on nuclear forces. Also prominently mentioned are: John Bardeen, Niels Henrik David Bohr, C. P. Boner, Gregory Breit, Walter M. Elsasser, Wendell Furry, George Gamow, Julian Knipp, Ettore Majorana, R. L. Moore, Otto Oldenburg, Melba Newell Phillips, Roberts, Simon Share, C. G. Smith, Arnold Johannes Wilhelm Sommerfeld, Carl Friedrich Weizsc̃ker, (Freiherr von); Institute for Theoretical Physics (Copenhagen), Niels Bohr Institutet, and Raytheon Corporation.