Nanophase materials and technology is the new application technology in recent 10 years along with the development of science and technology. Nanocomposites have attracted tremendous attention due to their potential applications in biomedical, catalytic, separation, chemical sensing, fuel cell, capacitor, microfabrication, tribological, resonant coupling, high flux gas transport and etc. Nanocomposite materials are complex of nanophase materials and other materials, it optimises the performance of traditional materials. Various nanocomposites have been synthesised in a wide range of polymerisation, sol-gel, deposition, magnetron sputtering, supercritical fluid, sonochemistry, laser, etc. Among these work, many strategies were addressed to improve nanocomposites mechanical properties by inclusions (fibers, whiskers, platelets, or particles). The embedding of inclusions in a host matrix to make composites, which gives material properties not achieved by either phase alone, has been a common practice for many years. Traditionally, composites were reinforced with micronsised inclusions. Recently, processing techniques have been developed to allow the size of inclusions to go down to nanoscale. With the recent developments in the nanoscience and nanotechnology fields, the correlation of composite properties with nanostructure has become a point of great interest. As a result, much of the work is still ongoing and there is yet to be a definite conclusion on the effect of nano-sized structure on nanocomposite systems. This book provides leading edge research from around the globe on this field.