  Recent theoretical and experimental improvements in the determination of
charm and bottom quark masses are discussed. A new and improved evaluation of
the contribution from the gluon condensate $< \frac{\alpha_s}{\pi} G^2>$ to the
charm mass determination and a detailed study of potential uncertainties in the
continuum cross section for $b\bar b$ production is presented, together with a
study of the parametric uncertainty from the $\alpha_s$-dependence of our
results. The final results, $m_c(3 \text{GeV})=986(13) $MeV and
$m_b(m_b)=4163(16) $MeV, represent, together with a closely related lattice
determination $m_c(3\;{\rm GeV})=986(6) $MeV, the presently most precise
determinations of these two fundamental Standard Model parameters. A critical
analysis of the theoretical and experimental uncertainties is presented.
