I discuss several aspects of strings as unified theories. After recalling the
difficulties of the simplest supersymmetric grand unification schemes I
emphasize the distinct features of string unification. An important role in
constraining the effective low energy physics from strings is played by
duality symmetries. The discussed topics include the unification of coupling
constants (computation of sin2θW and αs at the weak
scale), supersymmetry breaking through gaugino condensation, and properties of
the induced SUSY-breaking soft terms. I remark that departures from
universality in the soft terms are (in contrast to the minimal SUSY model)
generically expected.Comment: 22 pages. Talk given at the ``Workshop on Electroweak Physics Beyond
the Standard Model'', Valencia, 3-5 October 199