  Following a brief introduction we show that the observations obtained so far
with the Swift satellite begin to shed light over a variety of problems that
were left open following the excellent performance and related discoveries of
the Italian - Dutch Beppo SAX satellite. The XRT light curves show common
characteristics that are reasonably understood within the framework of the
fireball model. Unforeseen flares are however detected in a large fraction of
the GRB observed and the energy emitted by the brightest ones may be as much as
85% of the total soft X ray emission measured by XRT. These characteristics
seems to be common to long and short bursts.
