In 1954, Pierre Mendès France and Gabriel Ardant published their economic manifesto La science économique et l'action. Some twenty years later, they published a largely revised version, Science économique et lucidité politique. Each of these two editions is very much influenced by the time, these editions spaced out in time provide information on the evolution of the economic and political ideas of the two authors and the positioning of the two men in relation to Keynes and Keynesianism.