The article is in opposition with the orthodox vision of Marshall. First it shows why, theoretically and politically, willing to solve the social problems of his time, Marshall rejects the pure theory of Walras. After it shows how, from his lectures of the Classics, specially A. Smith, he builds his own general theory melting a wide range of economic, philosophic, sociologic and historic works. The paper exhibits its foundations formed by the integrated conception of man, society and cooperation as the motor of history. It specially shows its economic dimension which is the integration of labour economics, industrial economics and development economics, integration which is the originality and the most important contribution of marshall to economic theory. Finally, the paper insists on three great questions of marshallian economics which has been largely ignored or misunderstood : his real costs value theory (and its reappearence in Perroux works), his consumers' surplus as a scientific tool for a good governance of the society and his optimal growth theory as a political economy of development by the ways and means of the human resources promotion.
