  Thanks to its unprecedented spatial resolution, the Hubble Space Telescope
has ended a 20-year long stalemate by detecting the dynamical signature of
nuclear supermassive black holes (SBHs) in a sizeable number of nearby
galaxies. These detections have revealed the existence of a symbiotic
relationship between SBHs and their hosts, changing the way we view SBH and
galaxy formation. In this contribution I review which are the most pressing
outstanding issues in SBH research, and what are the technological requirements
needed to address them.
