The distribution is analysed traditionally by two types of modeIs. The first type is economic. The economists have tried to justify the agents ' presence in the distribution channels. Two functions are filled by the intermediaries for the exchange of the products between the producer and the consumer : cost minimisation, and utility maximization. The second type is behaviorist. The purpose is to explain the behavior of the firms 'channels. This perspective is complementary to the economic analysis, because it explains the mechanism of the distribution optimal configuration. The integration of these two approaches has been made by researchers. One of the most interesting models has been developed by E. Williamson. The strength of Williamson's work stems from recent developments in microeconomics which, through the transaction cost theory, has made a large part on. microeconomics directly applicable to the concerns of the main-line organisation theorist.