For centuries, supernovae have been studied primarily in the visual band thanks to
their strong optical emission that dominates the bolometric luminosity on timescales
of weeks following the explosion.  At the same time, some of the most profound
advances in our understanding of supernovae have been made possible through
observations at other wavelengths.  Here I will review the unique progenitor
diagnostics from radio and X-ray follow-up observations of supernovae, including
unusual pre-explosion mass loss histories of massive stars nearing dath and unveiling
the progenitors of SNe Ia.