2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/40090An overview is given of weak interaction physics of the light flavours. It starts with the definition of the CKM matrix and the measurement of its components in the light-flavour sector via semi-leptonic decays. The main part of the lectures is devoted to non-leptonic decays with a main emphasis on analytical calculations of $K\toππ$ and $K^0\leftrightarrow \kob$ mixing. It finishes with an overview of Chiral Perturbation Theory in $K\to3π$ and of rare Kaon decays.Lectures given at the Advanced School on QCD at Benasque, Spain, 3-6 July 2000. 27 pagesHigh Energy Physics - Phenomenologytext