B Decays, Flavour Mixings and CP Violation in the Standard Model

These lectures review the progress made in our present understanding of $B$ decays. The emphasis here is on applications of QCD to $B$ decays and the attendant perturbative and non-perturbative uncertainties, which limit present theoretical precision in some cases but the overall picture that emerges is consistent with the standard model (SM). This is illustrated by quantitatively analyzing some of the key measurements in $B$ physics.