Principles of crystal structure analysis are briefly stated from the standpoint that an amplitude of the diffracted rays represents a Fourier coefficient of the electron density distribution in the specimen. The descriptions of an anisotropic distribution of 3d electrons around the transition metals in complex compounds and minerals are presented as the most prominent examples of the precise analyses using conventional X-ray sources. Effects of the anomalous scattering are discussed and the way to distinguish the atoms of neighbouring atomic numbers is explained with the reason for its being effectively utilized at the Photon Factory. Some processes, especially for handling the data from the synchrotron radiation source, are mentioned.
