The literature on heterogeneous catalytic kinetics is enormous, For this reason, the author has chosen to be selective rather than comprehensive. This review discusses, semihistorically and by reference to illustrative papers, the development of ideas and trends in research within the chosen topics. By way of warning: The author's interest in kinetics and chemisorption has been developing for some 50 years [1–6], One hopes that prejudices have softened over the years, but one knows they have not disappeared.