It seems to be a strange enterprise to attempt write a physics book about a single number. It was not my idea to do so, but why not. In mathematics, maybe, one would write a book about ?. Certainly, the muon's anomalous magnetic moment is a very special number and today re?ects almost the full spectrum of e?ects incorporated in today's Standard Model (SM) of fun- mental interactions, including the electromagnetic, the weak and the strong forces. The muon g? 2, how it is also called, is a truly fascinating theme both from an experimental and from a theoretical point of view and it has played a...

This research monograph covers extensively the theory of the muon anomalous magnetic moment and provides estimates of the theoretical uncertainties.