This book is a systematic quantitative assessment of the dual difficulties of mitigating the aging of the Chinese population at the same time as controlling the overall size of the population. It argues that appropriately and gradually relaxing birth control policies in China can effectively mitigate the enormous economic pressure China will face from the aging of the population and simultaneously keep the size of the population within acceptable limits, thus realizing a strategic equilibrium between the pressures exerted by the size and aging of the population. This research uses an innovative quantitative indicator: the Aging and Economic Coordination Indicator (AECI) to measure macroeconomic pressure exerted by the aging of the population, and it is the first to use this quantitative method to systematically and quantitatively assess the degree and trends of, as well as controls over, economic pressure resulted the aging of the Chinese population over the time span 1980 to 2050.