Exclusive Decays of Charm and Beauty

Exclusive decays of B and D mesons are discussed with the focus on the theoretical problem how to calculate the relevant hadronic matrix elements of weak operators in the framework of QCD sum rules. The three lectures are devoted to 1. leptonic decays and decay constants 2. semileptonic decays and form factors 3. nonleptonic decays and nonfactorizable amplitudes. I shall introduce some of the basic concepts, describe various calculational techniques, and illustrate the numerical results. The latter are compared with lattice and quark model predictions and, where possible, with experimental data. Applications include the determination of V_{ub} from B -> \pi \bar{l} \nu_l and B -> \rho \bar{l} \nu_l, and an estimate of the phenomenological coefficient a_2 for B -> J/\psi K.