This informative new book describes the principles of X-ray diffraction and its applications to materials characterization. It consists of three parts. The first deals with elementary crystallography and optics, which is essential for understanding the theory of X-ray diffraction discussed in the second section of the book. Part 2 describes how "This book is a highly accessible introduction to XRD for materials research. It is written in concise and clear prose. The text creates a cohesive picture of XRD. After finishing this book, researchers will be able to understand the basics of many materials science and engineering research papers. . . . X-ray diffraction (XRD) is a powerful nondestructive characterization technique for determining the structure, phase, composition, and strain in materials. It is one of the most frequently employed methods for characterizing materials. This book distinguishes itself from other books on this topic by its simplified treatment and its coverage of thin-film analysis. It largely minimizes the mathematics and is profusely illustrated, making it a good entry point for learning the basic principles of XRD. The common thin-film structures (random polycrystalline, textured) and their relationships with the substrate (strain, in-plane rotation) are defined and explained. This makes it valuable to researchers who study thin-film deposition. The book includes example problems to reinforce the concepts covered, plus problems that can be assigned as homework." -J.H. Edgar, Kansas State University, USA, for MRS BULLETIN, February 2017