  A measurement of the mass of the W boson is presented which is based on a
sample of 5982 W -> e nu decays observed in pbar-p collisions at sqrt(s) = 1.8
TeV with the D0 detector during the 1992-1993 run. From a fit to the transverse
mass spectrum, combined with measurements of the Z boson mass, the W boson mass
is measured to be M_W = 80.350+-0.140(stat)+-0.165(sys)+-0.160(scale) GeV/c^2.
Detailed discussions of the determination of the absolute energy scale, the
measured efficiencies, and all systematic uncertainties are presented.
