  If supersymmetry turns out to be a symmetry of nature at low energies, the
first order of business to measure the soft breaking parameters. But one will
also want to understand the symmetry, and its breaking, more microscopically.
Two aspects of this problem constitute the focus of these lectures. First, what
sorts of dynamics might account for supersymmetry breaking, and its
manifestation at low energies. Second, how might these features fit into string
theory (or whatever might be the underlying theory in the ultraviolet). The
last few years have seen a much improved understanding of the first set of
questions, and at least a possible pathway to address the second.
