  We study classical N=2 string within the framework of the N=4 topological
formalism by Berkovits and Vafa. Special emphasis is put on the demonstration
of a classical equivalence of the theories and the construction of an action
for the N=4 topological string. The SO(2,2) Lorentz invariance missing in the
conventional Brink--Schwarz action for the N=2 string is restored in the N=4
topological action.
