Direct CP Violation and Rare $K$ Decays Perspectives

Quark mixing and CP violation has been a very active area of investigation over the past decades. Owing to the last round of experiments in $K$ and $B$ mesons, our understanding is now completely compatible with the existence of {\it just} one phase in the Cabibbo--Kobayashi--Maskawa mixing matrix. The precision of the tests in the quark sector can further improve thanks to the interplay of theory and experiments. Flavour transitions are so sensitive to short distance mechanisms that we are compelled to press for more quantitative tests of the Standard Model (SM) studying rare processes involving quarks and leptons. This is especially important because the direct exploration of the energy frontier is currently limited at the LHC energies and may remain so for many years to come.