Thermodynamical and Statistical-Mechanical Entropies of the General Static Spherically Symmetric Black Hole

The thermodynamical entropy of the general four-dimensional static spherically symmetric black hole is obtained by using the Euclidean path integral approach of Gibbons-Hawking, and its statistical-mechanical entropy is calculated according to the brick wall model of ’t Hooft. It is shown that the two entropies are not identical in general and the difference between them depends on the area of the horizon and the Ricci scalar curvature on the event horizon.