This is a study of the heterogeneous oxidation of alkenes on metal surfaces, specifically on surfaces of silver, platinum, and palladium. A variety of ultrahigh-vacuum methods are used, including temperature-programmed reaction techniques, vibrational spectroscopy, and photoelectron spectroscopy; synchrotron radiation techniques are used in selected cases to determine adsorbate geometries. Reaction intermediates are identified and isolated if possible, and rate constants for the elementary reaction steps are determined. Both selective oxidation and combustion processes are studied. Although this is a fundamental study not directed at any specific applications, the systems under investigation are used in a number of important industrial processes as well as in pollution control systems, including automotive catalytic converters. The new information generated here could influence the design of such systems.