  The exact general solution for a sigma model having the $2-d$ stringy black
hole (SBH) as internal manifold is found in closed form. We also give the exact
solution for the massless complex Sine-Gordon (MCSG) model. Both, models and
their solutions are related by analytic continuation. The solution is expressed
in terms of four arbitrary functions of one variable. (hep-th 9312085).
