Gamma-Ray Bursts

Gamma-ray bursts are the most luminous explosions in the Universe, and their origin and mechanism are the focus of intense research and debate. More than three decades after their discovery, and after pioneering breakthroughs from space and ground experiments, their study is entering a new phase with the recently launched Swift satellite. The interplay between these observations and theoretical models of the prompt gamma ray burst and its afterglow is reviewed.Comment: To appear in Rep. Prog. Phys., 74 pages, 11 figures, uses iopart.cls macros; revisions and updated reference