X-ray diffraction has been intimately tied with practical applications in the study of the structure of materials. All the way to the determination of the double helix structure of DNA in 1953, and of course, beyond that, to the present day.The book gives a thorough exposition of the theory of X-ray scattering. From the simple and early dynamical theory of Ewald to how electromagnetic radiation propagates and scatters in a crystal. Then there are discussions of dynamical theory of planar-wave Bragg scattering, And further talk on more advanced theories. Like how a spherical wave might scatter.Then many examples of applications are gone into, like building out X-ray optics, to be on an equivalent functional par with conventional visible spectrum optics. Much of the X-ray optical capability, like building monochromator crystals, X-ray wave guides, multilayers and Fresnel zone plates, is of relatively recent vintage; like the last 20 years.