2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/40762After sketching heavy quark expansions as applied to heavy flavour decays I emphasize the relevance of nonperturbative dynamics at the charm scale for exclusive $b\to c$ modes. I address the issue of quark-hadron duality for charm and discuss both the experimental and theoretical status of $D^0-\bar D^0$ oscillations. Finally I argue that comprehensive CP studies of charm decays provide novel portals to New Physics and suggest benchmark figures for desirable sensitivities.14 pages, LATEX, no figures, Invited talk given at KAON 2001, the 3th International Conference on CP Violation, Pisa, Italy, June 12 - 17, 2001High Energy Physics - Phenomenologytext