We formulate and study a new coarse (co-)assembly map. It involves a
modification of the Higson corona construction and produces a map dual in an
appropriate sense to the standard coarse assembly map. The new assembly map is
shown to be an isomorphism in many cases. For the underlying metric space of a
group, the coarse co-assembly map is closely related to the existence of a dual
Dirac morphism and thus to the Dirac dual Dirac method of attacking the Novikov
conjecture