We are looking ahead to a world where, in most of its modern parts, people will be many fewer and much older.

While rising health care spending is indeed a pressing issue, discounting population aging leaves out half the problem and ignores half the potential solutions.

A long-awaited world crisis of overpopulation is not developing. Indeed, declining population looms as a problem for many countries.

Over the foreseeable future, population replacement will be taking place--although not in the sense that demographers typically assign to the term.

Since the time of the Black Plague, the world’s population has headed in only one direction: up. But within a few decades, writes Ben J. Wattenberg in his new book Fewer: How the New Demography of Depopulation Will Shape Our Future (Ivan R. Dee, October 2004), the number...