ON QCD THERMODYNAMICS WITH IMPROVED ACTIONS

We discuss recent advances in the calculation of thermodynamic observa bles using improved actions. In particular, we discuss the calculation of the equation of state of the SU(3) gauge theory, the critical temp erature in units of the string tension, the surface tension and the la tent heat at the deconfinement transition. We also present first resul ts from a calculation of the equation of state for four-flavour QCD us ing an (3(a(2)) improved staggered fermion action and discuss possible further improvements of the staggered fermion action.