Анотація:
It is a short essay on statistical physics of complex systems a trend of studies which nowadays acquires all features of a well defined branch of science with its own subject of analysis system of notions and methods. The Ising model is chosen as a starting point for an expos e. Apart from conceptual simplicity, such a choice makes it possible to follow the formation and development of the phase transition theory in the Lviv school of statistical physics. Considerations adduced herein give a brief account of a talk given at the workshop on the occasion of academician I .R. Yukhnovskii s 85- th anniversary.