Two Higgs Doublet Models
  Present data do not rule out the light neutral Higgs particle $h$ or $A$ in the framework of the general 2HDM. The discovery reach/exclusion limits of the Yukawa process $Z\rightarrow f {\bar f} h/A$, ($f= b$ quark or $\tau$ lepton) at LEP I and of the gluon-gluon fusion at HERA is discussed. In addition the possible search for very light Higgs particle in $\gamma \gamma$ fusion at low energy NLC is described. 
Maria Krawczyk (Institute of Theoretical Physics, University of   Warsaw)