The investigation of atomic processes during the transfer from a gas-phase molecular species to an adsorbate phase with subsequent reactions at the surface, and the study of the adsorption characteristics of multicomponent surfaces from various perspectives are the main issues of this Joint Research Programme. In the various projects, the elementary steps of the chemisorption process, the energetics and dynamics of adsorption and desorption, as well as surface reactions of the chemisorbed atoms and molecules will be studied. The proposed investigations on the surface chemical bond between adsorbates and complex surfaces, and on the structure of the adsorption complex will contribute to elucidate the basic concepts of heterogeneous catalysis, which will be tested on specially prepared model systems. The selection of themes in the various projects traces the way from "ideal" to "real" surfaces, from simple chemisorption reactions to catalytically meaningful processes. In particular the interaction of small molecules such as H2, CO and O2 with palladium (Pd), rhodium (Rh), vanadium (V) and V-Pd alloy surfaces, as well as with metal-oxide surfaces will be investigated, both experimentally and theoretically.