  Observations of jets from quasars and other types of accreting black hole are
briefly summarized. The importance of beaming and $\gamma$-ray observations for
understanding the origin of these jets is emphasised. It is argued that both
the power source and the collimation are likely to be magnetic in origin,
although the details remain controversial. Ultrarelativistic jets may be formed
by the spinning hole and collimated by a hydromagnetic disc wind. Progress in
understanding jets has been handicapped by our inadequate knowledge of how
magnetic field really behaves under cosmic conditions. Fortunately, significant
insights are coming from solar observations, numerical simulation and
laboratory plasma experiments. Some possible, evolutionary ramifications are
briefly discussed and it is suggested that it is the mass of the black hole
relative to that of the galaxy which determines the eventual galaxy morphology.
