Primordial Black Holes and Gravitational Memory

We discuss the various ways in which primordial black holes may have formedin the early Universe and how the effects of such black holes can be used toplace constraints on cosmological models. We show that such constraints may beseverely modified if the value of the gravitational "constant" G varies withcosmological epoch, a possibility which arises in many scenarios for the earlyUniverse. The nature of the modification depends upon whether the value of Gnear a black hole maintains the value it had at its formation epoch(corresponding to gravitational memory) or whether it tracks the backgroundcosmological value. This is still uncertain but we discuss various approacheswhich might help to resolve the issue.