the purpose of this book is to serve as both an introductory course on the nanomechanics of deformed nanostructures and as a monograph providing a systematic overview of the current state of the art concerning the structure and deformation behavior of nanocrystalline materials. it is primarily concerned with up-to-date theoretical concepts and key experimental data on defects and plastic deformation processes in nanocrystalline matter. this book focuses on a very hot topic within materials science, and one that is both of great fundamental interest and of crucial importance for a wide range of nanotechnologies that rely on the unique mechanical properties of nanocrystalline materials.