Let 𝒞≡𝒞(n,Λ,δ0,V0) be the
set of all connected compact C∞n-dimensional Riemannian manifolds with |sectional
curvature| < Λ2, diameter < δ0, and volume > V0. The main result of this paper is
that this class 𝒞 has certain compactness, or more precisely, precompactness
properties. The class 𝒞 consists of only finitely many diffeomorphism classes so the
precompactness properties can be thought of as dealing with the set of metrics
satisfying the class 𝒞 requirements on a fixed differentiable manifold. The
main theorem of this paper is then that a sequence of such metrics always
has a subsequence which, after application of suitable diffeomorphisms of
M, converges to a limit metric. The regularity of the limit can be taken to
be C1,α, for all α with 0 < α < 1 and the convergence to be in the C1,α
norm.