Towards Understanding Gamma-Ray Bursts

$\gamma$-ray bursts (GRBs) have puzzled astronomers since their accidental discovery in the sixties. The BATSE detector on COMPTON-GRO satellite has been detecting GRBs for the last four years at a rate of one burst per day. Its findings has revolutionized our ideas about the nature of these objects. In this lecture I show that the simplest, most conventional and practically inevitable, interpretation of the observations is that GRBs form during the conversion of the kinetic energy of ultra-relativistic particles to radiation. The inner ``engine" that accelerates these particles is well hidden from direct observations and its origin might remain mysterious for a long time.