Open questions in charm decays deserving an answer

A list is given of those open questions concerning the dynamics of charm decays where there exists a strong need for an answer. Such a need is based on lessons to be learnt about QCD -- either in their own right or for a better understanding of B physics -- or on searches for New Physics with a small background from the Standard Model. The major items on this list are: lifetimes of the \Xi _c^{0,+} baryons; semileptonic branching ratios of D_s, \Lambda _c and \Xi _c hadrons and absolute branching ratios for those states; radiative decays D\rightarrow \gamma K^*,\, \gamma \rho /\omega , \, D_s \rightarrow \gamma \phi /\omega ,\, D\rightarrow l^+l^-K/K^*; D^0-\bar D^0 oscillations down to a sensitivity below 10^{-4} and CP asymmetries in non-leptonic D decays down to 0.1\%. Ongoing and already approved experiments will produce important new insights, which are unlikely to provide sufficient answers to all these questions yet. It is discussed how a third-generation fixed-target experiment like CHARM2000 or a \tau-charm factory can fill the bill.