Some of the four-dimensional Superstring solutions provide a consistent
framework for a Supersymmetric Unification of all interactions including
gravity. A class of them extends successfully the validity of the standard
model up to the string scale O(1017)GeV. We stress the importance
of string corrections which are relevant for low energy O(1)TeV
predictions of gauge and Yukawa couplings as well as the spectrum of the
supersymmetric particles after supersymmetry breaking.Comment: plain LATEX, no figures, 22 page