This book is dedicated to the fields of quantitative depth profiling, diffusion, and surface segregation in thin solid films. It contains a curated collection of original research papers and authoritative reviews that address the latest theoretical advancements and practical applications related to the aforementioned fields. The book is structured into three parts, each offering in-depth insights into its respective field.The first part concentrates on the quantitative analysis of depth profiling data, particularly on the application of the traditional and extended Mixing-Roughness-Information (MRI) model. It explores the theoretical fundamentals and practical implementations of depth profiling techniques, providing a thorough understanding of how the MRI model enhances the analysis of thin solid films. The second part shifts focus to the diffusion phenomena in thin solid films, examining the temperature dependence and the activation energy of the interdiffusion coefficient. It elucidates the impact of diffusion processes on the performance and reliability of materials in real-world applications. The third part delves into surface segregation, discussing the equilibrium and kinetic segregation in binary alloy thin films. It highlights the Modified Darken model and explores the influence of strain on surface and interface segregation in ultrathin alloy films.Suitable for scientists, engineers, and professionals, this book serves as a fundamental reference and a guide to the latest advancements in thin film analysis. It bridges the gap between theory and practice, offering readers the tools necessary for effective quantification and analysis in the ever-evolving field of materials science.