  Recent results of the hectic research activity about gamma-ray bursts will be
reviewed, with emphasis about the emission processes at the origin of the
observed gamma-rays. The conventional synchrotron shock scenario is found to
have problems, due to the very short cooling times of the emitting electrons,
which implies a predicted spectrum F(nu) proportional to nu^(-1/2), much
steeper than what is observed. It is therefore compelling to look for
alternative emission processes, such as quasi-thermal Comptonization, implying
the presence of mildly or sub-relativistic electrons, producing, through
multiple Compton scatterings, a spectrum proportional to nu^0 ending with a
Wien peak where photons and electron energies balance. The afterglow light,
instead, can be indeed due to synchrotron radiation, and a confirmation of this
is the recently detected optical linear polarization of the afterglow of GRB
990510. Some consequences of this discovery will be outlined. A quantum leap in
our understanding of the physics of gamma-ray bursts is expected to come with
SWIFT, a NASA-MIDEX dedicated satellite.
