  Hadronic decays of the $\tau$ lepton provide a clean source to study hadron
dynamics in an energy regime dominated by resonances, with the interesting
information captured in the spectral functions. Recent results on exclusive
channels are reviewed. Inclusive spectral functions are the basis for QCD
analyses, delivering an accurate determination of the strong coupling constant
and quantitative information on nonperturbative contributions. Strange decays
yield a determination of the strange quark mass.
