Amorphous-nanocrystalline alloys are a relatively new class of materials born from the rapid development of new technologies and different methods of producing amorphous and nanocrystalline powders and films, compacting, melt quenching, megaplastic deformation, implantation, laser, plasma, and other high-energy methods. This book considers methods of producing these materials (melt quenching, controlled crystallization, deformation effect, and pulse treatments (photon, laser and ultrasound), spraying thin films, and ion implantation). Theoretical and experimental studies describe plastic deformation mechanisms and physico-mechanical properties. Practical applications are also presented.