The term "functional gradient materials" was coined in Japan in the 1980s to describe a class of materials having spatially homogenous microstructures and properties. These materials can be used successfully in such applications as electronic devices, optical films, anti-wear and anti-corrosion coatings, thermal barrier coatings and biomaterials. The materials are fabricated with the use of nanoparticles, leading to greatly improved performance. Nanoparticle technology is not straightforward, however, demanding a modification of methods for processing and characterization. This book provides graduate students, postdoctoral fellows, engineers and senior scientists with an in-depth review of aspects of the field, ranging from synthetic methods to a variety of applications. The different approaches to material synthesis are described, giving the reader a better understanding of the complex phenomena involved. Characterization and the evaluation of properties are also discussed.