Everybody knows nowadays that the degree of development is measured according to a certain number of criteria, of which the most important one, and initially the only one. was the Gross National Product (or G.N.P.) of each country, related to the number of inhabitants. The arbitrarily-settled line some twenty years ago between the rich and the poor or, as called at that time, the “underdeveloped”, was based at the level of 1000 U. S. dollars per capita. The expression was badly accepted by those it described, because development confers a dignity which cannot be refused to anybody. That is why the following euphemism appeared: “developing countries”, as promising as it is little compromising. Later on, this exclusively economical criterion was moderated by several additives, linked to social structure, to the rate of elimination of illiteracy, and even to cultural factors.