Beaufils,Bruno Delahaye,Jean-Paul Mathieu,Philippe Complete Classes of Strategies for the Classical Iterated Prisoner's Dilemma Springer 33–41 1998 The Classical Iterated Prisoner’s Dilemma (CIPD) is used to study the evolution of cooperation. We show, with a genetic approach, how basic ideas could be used in order to generate automatically a great numbers of strategies. Then we show some results of ecological evolution on those strategies, with the description of the experimentations we have made. Our main purpose is to find an objective method to evaluate strategies for the CIPD. Finally we use the former results to add a new argument confirming that there is, in order to be good, an infinite gradient in the level of complexity in structure of strategies. Beaufils,Bruno Delahaye,Jean-Paul Mathieu,Philippe Our Meeting With Gradual: A Good Strategy For The Iterated Prisoner's Dilemma 1997