Kiefer (theoretical physics, U. of Cologne) describes the general features that a quantum theory of gravity is expected to show and gives an up-to-date overview of main approaches, including the quantization of Einstein's theory of general relativity and string theory. His general topics include a general description of quantum gravity, covariant approaches to quantum gravity, parametrized and relational systems, Hamiltonian formulation of general relativity, quantum geometrodynamics, quantum gravity with connections and loops, quantization of black holes, quantum cosmology, string theory, and quantum gravity and the interpretation of quantum theory.