X-ray Diffraction is an analytical technique that utilizes an inherent property of the x-ray beam - the wavelength - and the laws of physics that determine how that beam interacts with matter to characterize materials. Classically, the technique has been applied primarily to well-ordered crystalline materials to determine crystal structures, identify phase composition, measure stress, preferred orientation and crystallinity, but the field also encompasses the characterization of non- or semi-crystalline materials via small angle x-ray scattering (SAXS). Scattering experiments at very small angles can study electron density structures in materials on size scales greater than the electron density contrast due to atomic ordering observed in diffraction from crystalline materials and can provide information on size, shape, and distribution of electron density contrasted domains in polymers, dilute suspensions, gels, emulsions and more. Diffuse scattering to wide angles can study atomic structure in non-crystalline materials.