  We derive an exact formula for the dimensionality of the Hilbert space of the
boundary states of SU(2) Chern-Simons theory, which, according to the recent
work of Ashtekar et al, leads to the Bekenstein-Hawking entropy of a four
dimensional Schwarzschild black hole. Our result stems from the relation
between the (boundary) Hilbert space of the Chern-Simons theory with the space
of conformal blocks of the Wess-Zumino model on the boundary 2-sphere.
