M. : Science, Editor-in-Chief of Physical and Mathematical Literature, 1974. — 376 s. The fourth book of the series of monographs "Non-stationary stars and methods of their research" is devoted to non-stationary objects that play a special important role in stellar evolution (for example, supernovae) Much attention is paid in this book to the unique, unclassifiable stars. The place of the phenomenon of variability and nonstationarity in stellar evolution is also considered. A separate chapter is devoted to the phenomena of non-stationarity of recently discovered non-stellar objects, the nature of which there are only numerous hypotheses - these are quasars, galactic nuclei, etc.