Most estimates of wealth today are based upon gross domestic product, and many economists even see future wealth being created free of the constraints set by natural resources. Eric Davidson, scientist at the Woods Hole Research Center, calls such thinking "Marie Antoinette economics" and reveals its grave underlying fallacies. In valuing land or forests, for instance, we tend to discount their future value for our own children; in analyzing costs and benefits, the price of these natural resources upon which we ultimately depend is usually wrong; and damages to these resources are seen as "externalities." Davidson exposes these fallacies and offers a blueprint for a truly sustainable economy.