  Accreting black holes can release enormous amounts of energy to their
surroundings, in various forms. Such feedback may profoundly influence a black
hole's environment. After briefly reviewing the possible types of feedback, I
focus on the injection of kinetic energy through jets and powerful winds. The
effects of these outflows may be especially apparent in the heating of the
X-ray--emitting atmospheres that pervade clusters of galaxies. Analogous
heating effects, during the epoch of galaxy formation, could regulate the
growth of supermassive black holes.
