Heterostructured Metals: Processing, Interfaces, Defect Structures and Deformation Mechanisms presents an in-depth exploration of the intricate defect structures and deformation mechanisms found in nano and heterostructured metallic systems, with a particular focus on interphase boundaries. The book introduces readers to the atomic-level details, thermodynamics, and kinetics governing defect-interface interactions, and explains how these factors influence the mechanical behavior of metals. Through a combination of examples and forward-looking perspectives, it highlights the importance of these topics for future research and technological advancements in materials science. In addition to foundational concepts, this volume features a variety of model and engineering alloy systems, including both cubic and non-cubic crystals. It showcases state-of-the-art computational techniques at the atomistic and meso-scale levels, and describes advanced experimental approaches such as nanomechanical testing and in situ characterization. The book also outlines material synthesis methods using physical vapor deposition, as well as melt and deformation processing, providing a comprehensive resource for researchers and engineers in the field.