The swelling populations and sweeping social and economic trans formations which are now working themselves out in Latin America cannot fail to be reflected in those sensitive barometers of change, cities. More than one quarter of the total population now lives in cities of 20,000 or more and the present surge of urban growth shows little sign of having run its course. The traditional pattern of first-city supremacy has intensified rather than weakened with modernization. Despite programs of economic development, urban areas still have a low level of industrialization.