  Conventional approaches to supersymmetric model building suffer from several
naturalness problems: they do not explain the large hierarchy between the weak
scale and the Planck mass, and they require fine tuning to avoid large flavor
changing neutral currents and particle electric dipole moments. The existence
of models with dynamical supersymmetry breaking, which can explain the
hierarchy, has been known for some time, but efforts to build such models have
suffered from unwanted axions and difficulties with asymptotic freedom. In this
paper, we describe an approach to model building with supersymmetry broken at
comparatively low energies which solves these problems, and give a realistic
example.
