On the occasion of the 25th anniversary of our Institute, we are glad to send you the 42nd issue of our electronic review- the rives de l’ iriv. This issue is focused on games. We dedicate it to Ukraine, to the Ukrainians, and to their president. They teach us a tremendous lesson in courage and panache. Western democracies have forgotten that we must also fight with traditional means to defend our values and ideals. Return to basic rules – simplicity faced to the complexity of the world. War 3.0 (on social networks and on the Internet) or “hybrid warfare” is only one element in the elaborate panoply that strategists call “total warfare”. The «war games» are not the result of chance but come from a well-known theory in economics, the «game theory». On a very personal level, every Ukrainian must ask oneself an existential question of survival- the end of the month can sometimes reach the end of the world.