Present status of tau physics

The pure leptonic or semileptonic character of τ decays makes them a clean laboratory to test the structure of the weak currents and the universality of their couplings to the gauge bosons. Moreover, the semi-hadronic τ decays are an ideal tool for studying strong interaction effects in very clean conditions. An overview is given about the present knowledge about the τ lepton. Since very detailed reviews have been written recently, only a few subjects are discussed where the impact of the recent experimental data is more important. (K.A) 38 refs.; 1 fig.; 1 tab