  Dynamical breaking of supersymmetry was long thought to be an exceptional
phenomenon, but recent developments have altered this view. A question of great
interest in the current framework is the value of the underlying scale of
supersymmetry breaking. The "little hierarchy" problem suggests that
supersymmetry should be broken at low energies. Within one class of models, low
energy breaking be achieved as a consequence of symmetries, without requiring
odd coincidences. The low energy theories are distinguished by the presence or
absence of $R$ symmetries; in either case, and especially the latter one often
finds modifications of the minimal gauge-mediated spectrum which can further
ameliorate problems of fine tuning. Various natural mechanisms exist to solve
the $\mu$ problem in this framework.
