ABSTRACT
While the 20th century was the century of population growth—with the world’s population increasing from 1.6 to 6.1 billion—the 21st century is likely to see the end of world population growth and become the century of population aging. At the moment, we are at the crossroads of these two different demographic regimes, with some countries still experiencing high rates of population growth and others already facing rapid population aging. Demographic changes will make the 21st century like no other. Forecasting these changes, understanding their consequences, and formulating appropriate policies will, indeed, be challenging. This book is a step toward meeting those challenges.
