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 α/π, where α 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.