  Production of high-energy gravitational objects is a common feature of
gravitational theories. The primordial universe is a natural setting for the
creation of black holes and other nonperturbative gravitational entities.
Cosmic black holes can be used to probe physical properties of the very early
universe which would usually require the knowledge of the theory of quantum
gravity. They may be the only tool to explore thermalisation of the early
universe. Whereas the creation of cosmic black holes was active in the past, it
seems to be negligible at the present epoch.
