Quantum Gravity and String Theory

The recent developments in string theory are discussed and it is argued that string theory holds the most promising prospect of solving some of the important problems of quantum gravity in a unified manner. 1 e-mail: maharana@iopb.ernet.in The fact that two standard theorems of the subject, the non-existence of solutions describing assemblages of black holes except those of the extreme Reissner Nordstrom type and the rule jQj jM j for isolated charged black holes can be transgressed with a minimal violation of the smoothness requirements on the spacetime manifold by allowing only simple conical singularities suggests the fragility of the theorems of general relativity to the strict enforcement of smoothness conditions....Could one conclude from the very natural way in which strings emerge in the binary black-hole solution that strings are indeed predicted by general theory of relativity. ---S. CHANDRASEKHAR 1 Introduction The most outstanding unsolved problem in this century i..