  Fifty years ago, in 1952, the first significant paper on accretion flows was
written by Bondi. The subject has grown exponentially since then. In fact,
today many of the satellites engaged in space physics research look for
signatures of accretion processes in whatever objects are studied. In this
review, I will touch upon the significant developments in these years in this
subject, emphasizing mainly on accretion onto black holes. Since winds and
accretions are generally studied under similar framework, some references of
the winds/outflows studies will also be made.
