Even in the most primitive sociates

Even in the most primitive sociates the great majority of people satisfy a large part of their material needs by exchanging goods and service. Very few people indeed can make for themselves everything they need all their food, their clothes, thei housing and their tools. Ever since men started living in communities, they have been satisfying their needs by means of specialization and exchange. Incresingly each individual has produced more than he can consume himself of these special goods or services. He has supplied other members of the community with the surplus, and in exchange he has acquired the things he needs which others have produced