Sharp homology decompositions for classifying spaces of finite groups W. Dwyer University of Notre Dame Suppose that G is a finite group. A homology decomposition for BG is a way of constructing BG up to mod p homology as a homotopy colimit of classifying spaces of subgroups K of G. The decomposition is said to be sharp if the mod p homology spectral sequence associated to the homotopy colimit collapses to give an isomorphism between the H^*BG and colim H^*BK. We develop techniques for showing that a decomposition is sharp, and apply the techniques to a number of examples. (Preprint as of 6/96)