Quantum Gravity

'In spite of its sociological success string theory is still far from a solution of the problem of quantum gravity which should be considered as wide open. The book of Carlo Rovelli provides the basis, both at the technical and the conceptual level, for research in this fundamental problem of physics. The basic issues are clearly and deeply analyzed without any dogmatic stand and with great freedom of thoughts resulting in an invaluable opportunity to learn and think for both mathematicians and physicists.' Alain Connes, Collège de France, I.H.E.S. and Vanderbilt University