  We demonstrate that a measurement of the Bjorken process $e^+e^-,
\mu^+\mu^-\to ZH$ in the threshold region can yield a precise determination of
the Higgs boson mass. With an integrated luminosity of $100 fb^{-1}$, it is
possible to measure the Higgs mass to within 60 MeV (100 MeV) for m_H=100 GeV
(150 GeV).
