Crystals have fascinated us for centuries with their beauty and symmetry, and have often been invested with magical powers. The use of X-ray diffraction, first pioneered in 1912 by father and son William and Lawrence Bragg, enabled us to probe the structure of molecules, and heralded the scientific study of crystals, leading to an understanding of their atomic arrangements at a fundamental level. The new discipline, called X-ray crystallography, has subsequently evolved into a formidable science that underpins many other scientific areas. Starting from the determination of the structures of...