  The Isomorphism Conjecture is a conceptional approach towards a calculation
of the algebraic K-theory of a group ring RG, where G is an infinite group. In
this paper we prove the conjecture in dimensions n<2 for fundamental groups of
closed Riemannian manifolds with strictly negative sectional curvature and an
arbitrary coefficient ring R. If R is regular this leads to a concrete
calculation of low dimensional K-theory groups of RG in terms of the K-theory
of R and the homology of the group.
