Primordial Black Holes as Dark Matter Candidates
  We review the formation and evaporation of primordial black holes (PBHs) and
their possible contribution to dark matter. Various constraints suggest they
could only provide most of it in the mass windows $10^{17}$ - $10^{23}\,$g or
$10$ - $10^{2}\,M_{\odot}$, with the last possibility perhaps being suggested
by the LIGO/Virgo observations. However, PBHs could have important consequences
even if they have a low cosmological density. Sufficiently large ones might
generate cosmic structures and provide seeds for the supermassive black holes
in galactic nuclei. Planck-mass relics of PBH evaporations or stupendously
large black holes bigger than $10^{12}\,M_{\odot}$ could also be an interesting
dark component.
