Hadronic τ decays and QCD

New results for the τ hadronic spectral functions analysis using data accumulated by the ALEPH detector at LEP during the years 1991-94 are presented. The vector and the axial-vector spectral functions are determined from their respective unfolded, i.e., physical invariant mass spectra. The τ vector and axial-vector hadronic widths and certain spectral moments are exploited to measure αs and nonperturbative contributions at the τ mass scale. The best, and experimentally and theoretically most robust, determination of αs(Mτ) is obtained from the inclusive (V + A) fit that yields αs(Mτ) = 0.349 ± 0.018 giving αs(MZ) 0.1212 ± 0.0022 after the evolution to the mass of the Z boson. The approach of the Operator Product Expansion (OPE) is tested experimentally by means of an evolution of the τ hadronic width to masses smaller than the τ mass. (author)