Two volumes of lecture notes from the 1959 Brandeis University Summer Institute in Theoretical Physics. Courses taught by Francis Low, Julian Schwinger, E. C. G. Sudarshan, Leon Cooper, K. Huang, and H. J. Lipkin. Notes by W. Mills, A. Kaufman, J. C. Childress, Z. Fried, K. Huang, and M. Turoff. With courses on quantum theory of scattering, field theoretic methods, weak interactions, theory of superconductivity, hard sphere bose gas and liquid helium, and collective motion in many-particle systems.