There has been a sustained interest in the development of new catalysts having advantages to the major global problems like air pollution and other environmental issues. Three-way catalysts (TWC) for automotive exhaust treatment, which transform three environmentally hazardous gases namely CO, NOx and hydrocarbons to environmentally less hazardous form, is therefore a topic of intensive research. Ceria (CeO2) is an important ingredient in the formulation of TWC. The oxygen storage/release capacity (OSC) of ceria plays a vital role in this regard. Many technological and bioapplications have also been benefited from the unique redox and transport properties of ceria and ceria-based materials. This book emphasizes the design and evaluation of some unsupported and supported ceria based mixed oxide catalysts for catalytic applications, especially CO oxidation reaction.