Among existing x ray diffraction diagnostics nonperfections of crystals the specific location take methods are based on use of x-ray dynamic diffraction effects. From them the most sensitive are based on interferention. The Pendellosung and Moire fringes methods arise in consequence of coherent dynamic interaction of wave fields in single crystals. One of the main advantages of the Moire method is the extraordinary high sensitivity to insignificant deformations of crystal lattice ((Delta) d/d approximately 10-8) and atomic planes turns ((delta) approximately 0.01'). Created by a method of x-ray diffraction Moire the unique phase magnification permits us to directly observe the nuclear rows of crystal lattice. Until recently the attention of researchers attracted, basically, precise measurements of refraction parameters and dispersion amendments to nuclear scattering amplitudes, measurement of movy with large accuracy and refinement of Avogadro number, and the creation of new multi crystal interferometers. At the same time, little opportunities of x-ray interferometry at research of crystal structure defects were used. For the first time the opportunity of definition by method x-ray diffraction Moire of Burgers vectors of individual dislocation was demonstrated by M. Hart, Christiansen has studied the series of 60 degree(s) dislocation in Si on Moire images. Tensions in Si, caused by Ar ions implantation, were defined in the work. The purpose, which the authors of given reviews pursue consists in demonstration of new opportunities of x-ray three crystal interferometry in the investigation of single and complex defects.