Game Theory is a decision method. She assumes that the goal of each player is to maximize his benefit, whatever it may be. Friends, enemies, political parties, and states can play, in other words, anyone or anything can play. There is one problem in the analysis of games: it is very difficult for a player to know what promises benefit to everyone else, and some of us can hardly even imagine our own goals and benefits. Using many examples, Chaim Shapira shows what game theory is and how various interactions between decision makers can end.