The proposed book outlines the general basics of X-ray physics necessary for further study of special issues of X-ray application in science and technology: X-ray structural analysis, X-ray spectroscopic analysis, technical translucency, etc. In addition, the work on the fine structure of X-ray spectra is described in more detail, since these issues are not fully described in our literature. In this book, the author tried to pay special attention to the physical essence of the questions presented, believing that the latter is of paramount importance for any physicist. However, the mathematical apparatus of modern quantum mechanics allows you to solve many issues almost automatically, without understanding the meaning of the conclusion and the nature of the phenomenon. Therefore, for example, the author considered it useful in some cases to apply the principle of correspondence between classical theory and quantum mechanics even to the detriment of the rigor of the conclusions themselves. This approach is undoubtedly the best for an experimental physicist. A theoretical physicist will be able to get acquainted with a more rigorous theory in the special literature given at the end of the book. The reader assumes knowledge of electrodynamics, the basics of quantum mechanics and the theory of the atom, as well as differential and integral calculus. A few years later , After the publication of the first edition , In the field of X-ray physics, many new works have appeared. In particular, the study of the intensity of , Polarization and Spatial Distribution of the Continuous Spectrum , isochromate of continuous and characteristic spectra , X-ray Spectroscopy of Matter . During the annual reading of X-ray physics and X-ray spectroscopy courses at the University of Rostov revealed methodological shortcomings in the presentation of individual places, for example, in pp. 9 and 10 of Chapter 1, p. 1 of Chapter 2, p. Chapter 3, p. Chapters 4 and 5, p. For Chapter 6, the relevant sections have been corrected and in some places significantly supplemented. Also corrected some errors that crept into the first edition. The applications replaced the table of energy levels of the atom in the Rydbergs with a similar table of energies in electron volts, which is much more convenient when interpreting spectra. The rest of the tables are supplemented by data from works published in recent years. Added table of photon energies in electron volts for the brightest K- and L-series absorption lines.