Sachs asserts that it is in the long-term self-interest of rich countries to provide the assistance needed to eliminate extreme poverty. He also walks through the calculations to understand how much it will cost wealthy nations to eliminate poverty, reaching the same conclusion—that it is worth it any way he looks at it.

A first cut, giving a rough sense of the matter, shows that rich countries could insure every person on the planet has basic needs met for a total of $124 billion per year at a time when the annual income of the donor countries totaled approximately $20.2 trillion. Paying for the needs of the extremely poor to make up a deficit is not the approach that Sachs advocates by any means, but the difference between $20.2 trillion and $124 billion highlights the difference in scale between the rich countries’ resources and the poorest countries’ needs.

To make the case for bringing the extreme poor up to that first rung, however, requires additional methods of calculating cost. Sachs employs a method based on needs and World Bank data to suggest that $110 per person in need per year provides a reasonable estimate for three African countries, and he provides graphic justification for the number (296-98).