This review article provides one professional geographer's view of some of the major dilemmas that population growth has created for us during the past four decades. During that time, Earth's population grew by just over three billion, a number that is nearly ten times the current population of the United States. Arguably, that growth has come with some price tags that we've not yet reckoned with, from rapid depletion of oil and other energy resources to environmental degradation and atmospheric changes that are likely to worsen in the decades ahead. In trying to look at views of population growth and increasing affluence from different perspectives, it seems clear to me that there is growing evidence that in the long run the ecologists are going to be right and the economists wrong. Earth cannot sustain a growing population of ever-wealthier people living on a planet that has a finite supply of resources, and the twenty-first century is going to be the proving ground for this proposition. It would be prudent for us to consider various ways to slow population and economic growth so that we can bring our population into a closer balance with Earth's carrying capacity for our species.