This prologue reviews previous studies on the relationship between population dynamics and livelihood change, and provides background on the research and an overview of this book. To date, discussions of the relationship between population and livelihoods, particularly food supply, have been conducted from a global perspective. It has been argued that even as population increases, innovations in agricultural technology will prevent food shortages. However, it is difficult to apply discussions at the macro-global level to the micro-village level because people’s real lives are led in small-scale societies. Each small-scale social group has its own unique population dynamics, reproduction, and livelihood structure, and the complex interrelationships among them need to be elucidated. Despite the fact that small-scale social groups in emerging and developing countries constitute the majority of the world’s population, it has been difficult to understand population dynamics in these countries where statistics are not well developed. In this book, we discuss the population dynamics of small-scale social groups in Laos, which still have subsistence livelihood structures, by reconstructing the population, reproduction, and livelihoods of the past three generations and discussing the actual village dynamics where people live.