RESULTS AND FUTURE PROSPECTS FOR MUON (g – 2)

Spin physics had its beginnings in the famous experiments of Stern and Gerlach, which eventually resulted in the postulation of spin by Goudsmit and Uhlenbeck. The Stern-Gerlach experiment told us that the $g$-value of the electron was 2, but we now know that because of radiative corrections, the $g$-value of the leptons is slightly greater than 2, the lowest-order contribution being $\alpha/\pi$, where $\alpha$ is the fine-structure constant. Measurements of the magnetic dipole moments of the electron and muon have played a major role in our understanding of QED and of the standard model. In this talk I discuss the progress on measurements and theory of the magnetic dipole moment of the muon.