  Primordial black holes (PBHs) could account for all or part of dark matter,
as well as for some LIGO events. We discuss the spins of primordial black holes
produced in different cosmological scenarios, with the emphasis on recently
discovered possibilities. PBHs produced as a horizon-size collapse of density
perturbations are known to have very small spins. In contrast, PBHs resulting
from assembly of matterlike objects (particles, Q-balls, oscillons, etc.) can
have large or small spins depending on their formation history and the
efficiency of radiative cooling. We show that scalar radiation can remove the
angular momentum very efficiently, leading to slowly rotating PBHs in those
scenarios for which the radiative cooling is important. Gravitational waves
astronomy offers an opportunity to determine the spins of black holes, opening
a new window on the early Universe if, indeed, some black holes have primordial
origin.
