Advanced Nanocrystallines - From Design to Devices presents a comprehensive overview of the rapidly evolving field of nanocrystalline materials and their growing importance in modern science and engineering. Covering key topics such as nanocrystal design, structure–property relationships, crystal growth, defect engineering, sustainable nanomaterials, energy applications, and functional nanocomposites, this volume highlights both fundamental principles and emerging technological advancements. The book explores how nanoscale materials can be tailored to improve optical, electrical, mechanical, and catalytic performance across applications ranging from energy storage and conversion to electronics, photonics, and advanced devices. By integrating recent developments in materials synthesis, surface functionalization, and application-oriented research, this book provides valuable insights into the interdisciplinary nature of nanotechnology. Written for researchers, academicians, graduate students, and professionals in materials science, chemistry, physics, and engineering, this book serves as a useful reference for understanding current trends and future opportunities in research and innovation on advanced nanocrystalline materials.