Quark masses on the lattice: Light and heavy

Significant progresses in lattice calculations of light and heavy quark mas ses have been allowed by the introduction of improved actions and non-pertu rbative renormalization techniques. Current determinations of light quark m asses are accurate at the level of 20%, where the main source of uncertaint y is represented by the quenching error. The determination of the bottom qu ark mass is accurate at the impressive level of 2%. As final averages of la ttice results, I quote (m) over bar (u,d)(2 GeV) = (4.5 +/- 1.0) MeV, (m) o ver bar (s)(2 GeV) = (110 +/- 25) MeV and (m) over bar (b)((m) over bar (b) ) = (4.26 +/- 0.09) GeV.