  We study discrete group actions on coarse Poincare duality spaces, e.g.
acyclic simplicial complexes which admit free cocompact group actions by
Poincare duality groups. When G is an (n-1) dimensional duality group and X is
a coarse Poincare duality space of formal dimension n, then a free simplicial
action of G on X determines a collection of ``peripheral'' subgroups
F_1,...,F_k in G so that the group pair (G;F_1,...,F_k) is an n-dimensional
Poincare duality pair. In particular, if G is a 2-dimensional 1-ended group of
type FP_2, and X is a coarse PD(3) space, then G contains surface subgroups; if
in addition X is simply connected, then we obtain a partial generalization of
the Scott/Shalen compact core theorem to the setting of coarse PD(3) spaces.
