  We review results about the development and asymptotic nature of
singularities in `brane-bulk' systems. These arise for warped metrics obeying
the 5-dimensional Einstein equations with fluid-like sources, and including a
brane 4-metric that is either Minkowski or de Sitter or Anti-de Sitter. We
characterize all singular Minkowski brane solutions, and look for regular
solutions with nonzero curvature. We briefly comment on matching solutions,
energy conditions and finite Planck mass criteria for admissibility, and we
briefly discuss the connection of these results to ambient theory.
