  We discuss some of the the open questions and the roadmap in the physics of
primordial black holes. Black holes are the only dark matter candidate that is
known to actually exit. Their conjectured primordial role is admittedly based
on hypothesis rather than fact, most straightforwardly as a simple extension to
the standard models of inflation, or even, in homage to quantum physics, more
controversially via a slowing-down of Hawking evaporation. Regardless of one's
stance on the theoretical basis for their existence, the possibility of
primordial black holes playing a novel role in dark matter physics and
gravitational wave astronomy opens up a rich astrophysical phenomenology that
we lay out in this brief overview.
