I would like to use the formula S=A/4 to find the entropy of a black hole. But before I go ahead and believe that formula, there are a couple of subtleties that are troubling me. First of all, in just about every "classical" treatment of black hole thermodynamics, there is usually the underlying assumption that the spacetime is 4-dimensional, and asymptotically flat. Does anyone know if the above formula S=A/4 holds in higher-dimensional spacetimes that aren't asymptotically flat? Thanks.