Suppose that ℐn(C) is the class
of all Riemannian metrics on a given n-dimensional closed manifold such that their
associated Laplacians (on functions) have the same spectrum by counting
multiplicities and their sectional curvatures are uniformly bounded |K|≤ C by a
constant C > 0. We show that the isospectral class ℐn(C) is compact in the
C∞-topology. This generalizes our previous C∞-compactness result, which holds for
dimensions up to seven.