X-ray Nova Binary Systems

The physical properties of X-ray novae as close binary systems are analysed. Observational data in X-ray, UV, optical, IR and radio ranges are summarized. Modern theoretical considerations of the problem of X-ray novae, taking into account some new ideas and results, are described. Properties of optical stars in X-ray novae are analysed. Data about the masses of black holes in X-ray binary systems are summarized. Possible evolutionary links between WR stars in close binary systems and X-ray novae are analysed.