The year 1800 marks the beginning of the first period in human history of sustained and simultaneous economic and demographic growth. It is a period in which population growth far surpassed anything experienced previously and has led to a very full world, with 7 billion inhabitants at present and possibly as many as 10 billion by the end of this present century. This course examines the factors that allowed humans to break free from the "Malthusian trap" that characterized all pre-modern human societies. We then trace the arc of economic and population growth into our own time. Our focus will be on the often under-appreciated role of the Demographic Transition in the development first of Europe, then Asia and now Africa. Its pervasive implications for social and economic modernization of the developed and the developing worlds are discussed in detail. We also examine some long-term implications of the Demographic Transition for human populations how these may differ in different world regions during the 21st Century.