P.A.M. Dirac's Impact on Physics

Paul Dirac (1902-1984) was not as well known as the other founding fathers of quantum mechanics in the 1920's, but his contributions were equally important, and he won the Nobel Prize in 1933, at the same time as Heisenberg and Schr\"{o}dinger. He spent the last fifteen years of his life in the SESAPS region, in Tallahassee, Florida. I will describe his life and his work, comment on his style, and recount how he arrived at the relativistic wave equation. I will describe one of my personal encounters with Dirac and, if I can manage not to bungle it, show a physics demonstration that is relevant to the application of group theory to quantum mechanics, a subject that Dirac and other detractors scathingly referred to as \textit{Gruppenpest.}