Progress in catalysis is described as the result of the interplay between societal demands and autonomous scientific developments. A short historic review of the succession of new catalytic processes that took place in the course of this century is given. Also the development of catalysis as a scientific discipline is sketched. Three branches of catalysis are distinguished. Physical chemistry developing into catalytic reaction engineering, kinetics and catalyst characterization, inorganic chemistry as a basis to catalyst preparation and coordination chemistry leading to organometallic chemistry and homogeneous catalysis. It is shown how catalysis science changes from a descriptive science, focusing on structure-performance relations to a predictive science, with a basis in molecular mechanistic understanding. Major modern concepts in fundamental catalysis are discussed. The paper is concluded with an outline of trends in the different scientific catalytic disciplines. The need to integrate disciplinary approaches into system approaches is pointed out.