  We review the renormalization of one-loop effective action for gravity
coupled to a scalar field and that of the Bekenstein-Hawking entropy of a black
hole plus the statistical entropy of the scalar field. It is found that the
total entropy of the black hole's geometric entropy and the statistical entropy
yields the renormalized Bekenstein-Hawking area-law of black hole entropy only
for even dimensional Reissner-N\"{o}rdstrom (Schwarzschild) black holes. We
discuss the problem of the microscopic origin of black hole entropy in
connection with the renormalization of black hole entropy.
