6 G A M M A - R AY B U R S T S A S P R O B E S OF THE UNIVERSE The cosmos is full beyond measure of elegant truths; of exquisite interrelationships; of the awesome machinery of nature. --Carl Sagan, "The Shores of the Cosmic Ocean" episode of Cosmos: A Personal Voyage (1990) Until now we have concentrated on the observations and theory of GRBs. The events have shown themselves as a complex, panchromatic phenomenon that can arise from a variety of different progenitors in both the nearby and distant Universe. The GRB community has succeeded