Implications of recent observational discoveries for the nature and origin of gamma-ray bursts

The discoveries that GRBs have X-ray, optical and radio afterglows have connected the study of GRBs to the rest of astronomy, and revolutionized the field. In this review, I discuss the implications that the observation of these afterglows have for burst energies and luminosities, and for models of the bursts and their afterglows. I describe recent evidence linking the long, softer, smoother GRBs detected by BeppoSAX and core collapse supernovae. Finally, I summarize recent work showing that, if these GRBs are due to the collapse of massive stars, they may provide a powerful probe of the very high redshift universe.