  Radio observations of gamma-ray burst (GRB) afterglows provide both
complementary and unique diagnostics of the afterglow physics and environment
of the burst. Here we concentrate on three unique aspects of GRB energetics and
environments afforded by radio and submillimeter observations: the
non-relativistic evolution of the fireball, the density profile of the
circumburst medium, and the study of obscured star formation in GRB host
galaxies.
