The year 1983 marked the end of a particularly noteworthy decade in the development of elementaryparticle physics. Between 1973 and 1983 there were three accomplishments of special, perhaps historic, importance:
▹ The theoretical and experimental unification of the forces that govern all of the phenomena of both electromagnetism and the weak interactions.
▹ The recognition that the strongly interacting particles (nucleons, mesons and other hadrons) are in fact made of still smaller entities, now known as quarks, and the development of a tentative theory of the force between the quarks.
▹ The identification of three almost identical (except for mass) families of elementary “particles,” each family consisting of two quarks, one charged lepton (the electron, the muon or the tau) and a neutrino.