In recent years, one of the great developments in general relativity was the discovery of a close relationship between black hole
mechanics and the ordinary laws of thermodynamics. The existence of this close relationship between these laws may provide us with
a key to our understanding of the fundamental nature of black holes as well as to our understanding of some aspects of the nature of
thermodynamics itself. Also, it is notable that the black hole is an object that is considered in classical and quantum point of view and so
one hopes to gain insight into the nature of quantum gravity by studying the thermodynamics of black holes.