This book provides a clear and very broadly based introduction to crystallography‎,‎ light‎,‎ X‎-ray and electron diffraction ‎- a knowledge which is essential to students in a wide range of scientific disciplines but which is otherwise generally covered in subject‎-specific and more mathematically detailed texts‎.‎ The text is also designed to appeal to the more general reader since it shows‎,‎ by historical and biographical references‎,‎ how the subject has developed from the work and insights of successive generations of crystallographers and scientists‎.‎ The book shows how an understanding of crystal structures‎,‎ both inorganic and organic may be built up from simple ideas of atomic and molecular packing‎.‎ Beginning with ‎(‎two dimensional‎)‎ examples of patterns and tilings‎,‎ the concepts of lattices‎,‎ symmetry point and space groups are developed‎.‎ ‎'‎Penrose‎'‎ tilings and quasiperiodic structures are also included‎.‎ The reciprocal lattice and its importance in understanding the geometry of light‎,‎ X‎-ray and electron diffraction patterns is explained in simple terms‎,‎ leading to Fourier analysis in diffraction‎,‎ crystal structure determination‎,‎ image formation and the diffraction‎-limited resolution in these techniques‎.‎ Practical X‎-ray and electron diffraction techniques and their applications are described‎.‎ A recurring theme is the common principles‎:‎ the techniques are not treated in isolation‎.‎ The fourth edition has been revised throughout‎,‎ and includes new sections on Fourier analysis‎,‎ Patterson maps‎,‎ direct methods‎,‎ charge flipping‎,‎ group theory in crystallography‎,‎ and a new chapter on the description of physical properties of crystals by tensors ‎(‎Chapter 14‎)‎‎.‎