Quantum gravity - What are the problems?

One of the biggest open problems in physics is the consistent unification of quantum theory with general relativity, resulting in a theory of "quantum gravity". Such a theory would have an important bearing on the physics of the early universe and the understanding of black holes. Moreover, it would possess deep relevance for our fundamental understanding of nature.

In my talk I shall attempt to present the general problems in constructing a quantum theory of gravity as well as the main conceptual ingredients of such a theory. I shall then shortly review the main approaches and attempt a critical evaluation of their status.