What is it all about?; the avalanche; the two basic, time-honoured process capability indices - Cp and Cpk; first generation modification - Cpm and its clone relatives; the benefit (or the curse) of normality and symmetry and how to get rid of it when necessary; a superstructure and unified approach to process capability indices; the dangerous but unavoidable area - multivariate process capability indices; process capability studies in industries throughout the world; just say "yes".