This document summarizes the main ideas contained in the inter-agency publication with the same title coordinated by the Economic Commission for Latin America and the Caribbean (ECLAC), which included contributions from all of the international organizations that are present in the region (United Nations, 2005). This book examines the progress made between 1990 and 2004 by the Latin American and Caribbean countries and by the region as a whole in pursuit of the Millennium Development Goals and their respective targets. Together with this review, it analyses the main features of the region's underdevelopment, points out the marked differences in levels of well-being both between countries and within them, and offers general guidelines for the design of policies to address the lags which hinder the countries' economic and social development.