Recently Gang Tian introduced a new method in Minimal model program by using
Kahler Ricci flow theory. He proposed a program of finding canonical metrics on canonical models of projective varieties of positive Kodaira dimension. He also extended this program for minimal surfaces by using modefied Kahler Ricci flow. He
introducced generalized Kahler Einstein Metric by using Weil-Petersson metric on moduli space of Calabi Yau manifolds and considered the existence of generalized Kahler Einstein metrics. I try to explain his theory.