Diffusion, the movement of atoms in a material, is an integral part of many metallurgical and materials treatment processes. Understanding diffusion mechanisms helps to control and improve materials properties. This book offers a comprehensive overview of diffusion in the synthesis and analysis of materials (metals and non-metals) from the fundamentals through applications. Discusses defects in materials, fundamentals of the diffusion process, and different diffusion mechanisms active in metallic alloys Describes diffusion within non-metallic materials, including ceramics, polymers, and semiconducting materials, with special emphasis on silicon Covers diffusion along high-energy paths, short-circuiting diffusion, such as grain boundaries, dislocations, and materials surface Explores diffusion under thermal and electrical gradients and explains how this information is useful for materials purification Details the application of diffusion on carbides during the thermal and thermomechanical treatments of steels Includes problems and solutions for each chapter to reinforce reader's comprehension Written with less emphasis on complex mathematical equations, this text is accessible to researchers and students in materials, mechanical, and related engineering disciplines studying the phenomenon of diffusion in materials and its application in the engineering of materials.