This book presents a comprehensive summary of the results obtained over the last sixty years in the field of kinetics and mechanisms of organic and inorganic reactions catalyzed with metal complexes. The specificity of the catalytic reaction kinetics in the presence of the different form of mono- and polynuclear metal complexes and nanoclusters is discussed. The multiroute mechanisms and the methods of their identification as well as approaches to the polyfunctional catalytic systems kinetics are presented. In addition, the mechanisms of active centers formation and the real, non-ideal catalysts action are systematized and classified. The role and the place of kinetic methods in mechanism studies and the foundation of a rational strategy of theoretically-based kinetic model design is also considered. The kinetic models and mechanisms of many homogeneous catalytic processes employed in synthetic and commercial chemistry are presented.