How will population change our world over the course of this century, reshaping politics, economies, and international relations?Questions about population have become increasingly common in today's news and policy debates. Why are women around the world having so few children? Are immigrants necessary for economic growth, or are they a threat? Will China's rise be affected by the decline of its population? Can America and Europe afford the pensions and health care costs for their aging populations? How many people can the earth support?To find answers, author Jack A. Goldstone does more than just examine the numbers. Through the lens of political demography, he reveals how population change will reshape immigration, family life, economic prosperity, health and longevity, the environment, and the future of global leadership. The potential solutions are complex and require a measure of compromise and sacrifice from various groups today to ensure a better future for all tomorrow. Demography is not destiny, but it poses unavoidable challenges. Understanding these challenges and how we can respond to them is the key to creating a better future for us all. Goldstone offers a clear-eyed view of what lies ahead. The shape of the societies we live in fifty years from now will be determined by the choices we make today. We can either recognize the trends that we have put in motion and respond to them, or ignore them and act surprised when they overwhelm us.