On the precise determination of the Fermi coupling constant from the muon lifetime

The determination of the Fermi coupling constant, GF, is examined in the light of recently calculated two-loop QED corrections and planned experiments to measure the muon lifetime to a level below 1 ppm. The methods used in the calculation of the QED corrections are described in detail. Sources of the dominant theoretical and experimental uncertainties are identified. Finally the incorporation of GF into analyses using the full electroweak Standard Model is discussed