  In this lecture we investigate the formation and evolution of black holes in
star clusters. The star clusters under consideration are generally rich,
containing more than 10^4 stars, and with a density exceeding 10^4 stars/pc^3.
Among these are young dense clusters (YoDeCs), globular cluster and the nuclei
of galaxies. We will also address the the possible evolutionary link between
stellar mass black holes, via intermediate mass black holes to supermassive
black holes, mainly focus on the ecology of star clusters.
