  The various possibilities for the progenitors of gamma-ray bursts (GRBs)
manifest in differing observable properties. Through deep spectroscopic and
high-resolution imaging observations of some GRB hosts, I demonstrate that
well-localized long-duration GRBs are connected with otherwise normal
star-forming galaxies at moderate redshifts of order unity. I test various
progenitor scenarios by examining the offset distribution of GRBs about their
apparent hosts, making extensive use of ground-based optical data from Keck and
Palomar and space-based imaging from the Hubble Space Telescope. The offset
distribution appears to be inconsistent with the coalescing neutron star binary
hypothesis but statistically consistent with a population of progenitors that
closely traces the ultra-violet light of galaxies. This is naturally explained
by bursts which originate from the collapse of massive stars. This claim is
further supported by the unambiguous detections of emission ''bumps'' which can
be explained as supernovae that occur at approximately the same time as the
associated GRB; if true, GRB 980326 and GRB 011121 provide strong observational
evidence connecting cosmological GRBs to high-redshift supernovae and implicate
massive stars as the progenitors of some long-duration GRBs. Interestingly,
most alternative models of these bumps require wind-stratified circumburst
media; this too, implicates massive stars. In addition to this work, I also
constructed the Jacobs Camera (JCAM), a dual-beam optical camera for the
Palomar 200-inch Telescope designed to follow-up rapid GRB localizations
(abridged).
