Rare Decays, CP Violation and QCD

We discuss several aspects of rare decays and CP violation in the standard model including the impact of the recent top quark discovery. In particular we review the present status of next-to-leading QCD calculations in this field stressing their importance in the determination of the parameters in the Cabibbo-Kobayashi-Maskawa matrix. We emphasize that the definitive tests of the standard model picture of rare decays and CP violation will come through a {\it simultaneous} study of CP asymmetries in $B_{d,s}^0$ decays, the rare decays $K^{+}\to {\pi }^{+}\nu \bar{\nu }$ and $K_L\to {\pi }^0\nu \bar{\nu }$, and $(B^0_d-\bar B^0_d)/(B^0_s-\bar B^0_s)$.