  Hadronically decaying tau leptons are of prime importance in numerous physics
analyses in ATLAS. The spectrum of the possible applications of hadronically
decaying tau leptons reaches from Standard Model measurements, including Higgs
searches, to searches for physics beyond the Standard Model.
  The basic principles behind the sophisticated tau reconstruction and
identification techniques, which are specifically designed to identify
hadronically decaying taus and reject various background processes, are
delineated here along with current data-driven estimates of their respective
performance.
