  We consider a class of black hole solutions to Einstein's equations in d
dimensions with a negative cosmological constant. These solutions have the
property that the horizon is a (d-2)-dimensional Einstein manifold of positive,
zero, or negative curvature. The mass, temperature, and entropy are calculated.
Using the correspondence with conformal field theory, the phase structure of
the solutions is examined, and used to determine the correct mass dependence of
the Bekenstein-Hawking entropy.
