Metal nanoparticles exhibit unique optical, electronic and catalytic properties which are primarily based on their small size and their high surface to volume ratio. The properties of these materials are often different from corresponding bulk materials of the same kind and are usually influenced by the particle size. Developments of metal/metal oxide nanostructures, which can be synthesized by cost effective synthesis methods and with well-defined morphologies, have attracted considerable interest. The structural, microstructural characteristics, properties and their inter-relationship lead to the applications in electronic medicine, magnetic and photonic devices. This book presents the synthesis, characterization and applications of metal and metal oxide nanostructures.