Research of activity of cataclysmic variables, supersoft X-ray sources and other binary high energy sources including the prototypic source HZ Her/Her X-1, with the impact for the development and specification of their physical models, deeper understanding of the physical processes controlling the activity of these objects and their physical evolution. These analyses often made use of suitably applied archival optical and X-ray data for investigation of the physical behaviour of selected sources on various time scales, including unique analyses of activity of systems on the time scales of the order of several decades. This led to a deeper understanding of the physical processes which act on such long time intervals. Also the CCD data obtained by our instruments in the Astronomical Institute were utilized, including the international observing campaigns. All this gave rise to a series of publications and scientific communications.