ABSTRACT
Economic development is an idea that became formalized in the mid-twentieth century, as the colonial empires began to break down and the more industrialized countries gradually took on a changed set of attitudes toward the parts of the world that had not experienced industrialization. The economic relations between colonies and their rulers had been dominated by the desire of the ruling countries to enrich themselves, first, through extraction of raw materials, and, second, through the creation of markets for goods that they wished to export. In practice, however, economic growth is almost always accompanied by, and is often caused at least in part by, an increase in aggregate demand. Economists sometimes think about output as being generated according to a "production function", which is a mathematical relation between various inputs and the level of output. This economic growth has been very unevenly distributed among countries, as well as among people within countries.
