The atomistic understanding of chemistry is based on chemical structure, spectroscopic properties, and reaction kinetics. There is a large amount information on the kinetics of heterogeneous catalysis. Then, too, various different methods of spectroscopic amalysis have been ingeniously applied to problems in surface chemistry. It is the purpose of this paper to show how spectroscopic methods, particularly infrared and electron energy loss spectoroscopy, may help to identify the structure of surface species which are closely related to the heterogeneous catalysis of carbon monoxide hydroge-nation, formic acid decomposition, and olefin isomerization.