The weak interaction: Its history and impact on physics

It is a pleasure and an honor for me to give this lecture in honor of Oscar Klein who made major contributions to field theory, quantum electrodynamic s and particle physics, including weak interactions. He was the first one t o observe that the mu decay and the beta decay could be described by the sa me interaction with the same coupling constant; this led to the discovery o f the Universal Fermi Interaction. Perhaps I should begin my discussion of the history of weak interactions by separating it into three periods: (1) Classical Period, 1898-1949. (2) Transition Period, 1949-1956. (3) Modern Period, 1956-.