This is the first book about functional nanostructures. Nanocrystalline materials exhibit outstanding properties and represent a new class of structural materials having a wide range of applications. There is considerable interest in developing nanocrystalline materials to be used as functional materials in aerospace applications, automotive industry, wear applications, MEMS, etc. The future progress and eventual production of these high-tech applications of nanocrystalline materials depends on development of new fabrication methods and on broader, practical understanding of the underlying nano-scale and interface effects causing their unique mechanical properties. This book is written to be useful for researchers and graduate students in the field of Nanomaterials Science and Nanotechnologies, and engineers involved in production and processing of nanomaterials.