WHAT EINSTEIN DID NOT KNOW

This public lecture is about 100 years of research on elementary particles and fundamental forces, beginning with the identification of the electron about 1900 and extending to the astonishing discovery of Dark Matter in the late 1900s. The author talks about the elementary particle concept; the discoveries of leptons, quarks and force carrying particles; and some of the experimental technology used. The author tells of his own research, the discovery of the tau lepton, the long, inconclusive search for fractional charged particles and his new involvement in astronomical research on Dark Matter. He concludes by looking ahead to old unsolved puzzles and new questions on the fundamental nature of matter and force that face us in the 21st Century.