This book discusses the processes, properties and applications of plastic deformation. The first chapter provides short notes on the grains modification induced by local plastic deformation. Chapter Two examines energy accumulation and mechanisms of plastic deformation in organic glassy polymers. Chapter Three investigates the microstructure and texture of the pure magnesium foils obtained by room temperature reverse extrusion followed by cold rolling. The final chapter discusses utilization of severe plastic deformation (SPD) to produce ultrafine grained structures using top-down approach in novel metal forming processes.