  The evolution of nonlinear density fluctuations around the Jeans mass shortly
after cosmological recombination is analyzed using a 3D
hydrodynamics/dark--matter code. The Cosmic Background Radiation (CBR) exerts
Compton friction on free electrons due to peculiar velocities. The dynamics
therefore depends strongly on the gas ionization history. Under a variety of
ionization conditions and in systems with or without non-baryonic components,
the baryons lose angular momentum efficiently and collapse to form a compact
optically--thick object which would probably quickly evolve into a massive
black hole. Attention is concentrated on elucidating some of the novel physical
effects in early cosmological collapses, but ways in which more realistic
calculations might be made and in which the scenario could be incorporated into
a more complete cosmogonic model are discussed.
