This book is a fundamental work for those seeking to understand the structure and properties of crystalline materials from a rigorous and systematic approach. Its coverage, which ranges from the physical principles of X-rays to structural refinement using the Rietveld method, provides a solid theoretical and practical foundation. The inclusion of symmetry group analysis and the study of elasticity reinforce its value in areas such as electronics and engineering. With an educational and precise approach, this work becomes an indispensable reference for materials characterization.