  We report the discovery of the nearby long, soft GRB 100316D, and the
subsequent unveiling of its host galaxy and associated supernova. We study the
extremely unusual prompt emission with time-resolved gamma-ray to X-ray
spectroscopy and find that a thermal component in addition to the synchrotron
spectrum is required. The host galaxy is a bright, blue galaxy with a highly
disturbed morphology. From optical photometry and spectroscopy we provide an
accurate astrometry and redshift, and derive the key host properties of star
formation rate and stellar age. We compare our findings for this GRB-SN with
the well known previous case of GRB 060218. GRB 100316D is an important
addition to the current sparse sample of spectroscopically confirmed GRB-SNe,
from which a better understanding of long GRB progenitors and the GRB-SN
connection can be gleaned.
