Includes Figure caption index 418-432p.; Table title index 433-435p.

This book is based on the author's research and teaching experience over many years. Using geometric concepts and methods it systematically analyses and deduces the crystal symmetry principle and the crystal diffraction theory, establishing distinctive three-dimensional concepts which are easy to understand, grasp and apply.The whole book is divided into three parts: geometric crystallography principles, micro-space symmetry principle and basic principle of X-ray diffraction in crystal. The first and second section carry an in-depth discussion and analysis on macro-symmetry, micro-symmetry and symmetrical composition law of crystal respectively using the principle that the symmetric distribution of equivalent point in space is consistent space symmetry. The first two sections also systematically deduce the thirty two point groups and two hundred thirty micro-space symmetric combinations. Section three details Laue scattering equation and Prague reflection equation and describes practical use of several important single crystal diffraction methods and apparatus on the basis of mutual relations between crystal lattice and its reciprocal lattice, using reciprocal lattice and reflection ball mathematical model and their interaction relation.In addition, starting from the principle that reciprocal lattice point system disappearance caused by translation vector in microscopic crystal space, it states system extinction law of diffraction, and deduces one hundred twenty diffraction groups. This book lays the foundation for study of crystallography, crystal structure analysis and protein crystallography. It is a must-have for undergraduate and postgraduate students and a very good reference for researchers engaged in relevant studies.