Reprints collected by Hans Bethe pertaining to physics, astrophysics, nuclear physics, quantum theory, supernovae, and solar energy. Authors include Niels Bohr, Alfred Einstein, Paul Peter Ewald, Enrico Fermi, Richard P. Feynman, William A. Fowler, George Gamow, Werner Heisenberg, Irving Langmuir, Edwin M. McMillan, Carleton C. Murdock, J. Robert Oppenheimer, and Rudolf E. Peierls.