Thin films of a variety of technologically important oxide systems (chromium oxide, barium oxide, titanium oxide and iron oxide) have been grown under ultra-high vacuum conditions by vapour deposition techniques. The surface structure and chemistry of these oxide films have been characterised by x-ray photoelectron spectroscopy( XPS), low energy electron diffraction (LEED), reflection absorption infrareds pectroscopy(R AIRS) and temperaturep rogrammedd esorptions pectroscopy (T'PD). These studies have included investigation of both the clean oxide surface and their interaction with small molecules. Well-defined chromium oxide films were produced and the surface structure of these films was found to be consistent with the (0001) surface Of C17203T- he studies of barium oxide have revealed a complicated oxygen chemistry with transformation between different forms being brought about by different preparation conditions and post-treatments including heating and exposure to 02, C02 and CO. Well-defined iron oxide films have been generated and in addition to their characterisation such films have been used as a support for the deposition of silver metal nanoparticles. The surface chemistry of this mixed metal/oxide Ag/FeO., system has been probed in particular by the adsorption of propene at sub-ambient temperatures. The ultimate aim of this researchw as to studyt hesem etal oxide thin films as a means to elucidatinga deeperf undamentalu nderstandingo f the surfacec hemistryo f these systemsw, hich is of both academica nd industriali nterest.