This well-researched article describes the discoveries that made 1932 a watershed year in the development of nuclear physics. Breakthroughs included the discovery of deuterium, the positron, and the neutron. The article provides details about each discovery and the atmosphere of excitement that prevailed that year. It also discusses the important role played by new particle accelerators, primarily Ernest Lawrence's cyclotron at the University of California, Berkeley. The article includes photographs, and excerpts of letters and interviews by some of the physicists who made those discoveries.