The labor of nature is paid, not because she does much, but because she does little. In proportion as she becomes niggardly in her gifts, she exacts a greater price for her work. Where she is munificently bene- cent, she always works gratis. 1 David Ricardo This book interprets nature and the environment as a scarce resource. Whereas in the past people lived in a paradise of environmental superabundance, at present environmental goods and services are no longer in ample supply. The environment fulfills many functions for the economy: it serves as a public-c- sumption good, as a provider of natural resources, and as receptacle of waste. These different functions compete with each other. Releasing more pollutants into the environment reduces environmental quality, and a better environmental quality implies that the environment use as a receptacle of waste has to be restrained. Consequently, environmental disruption and environmental use are by nature allocation problems. This is the basic message of this book.