William Nordhaus has gone further than any economist to date at building a dynamic integrated model of the world’s climate and economic systems, with some one-way linkages to agricultural systems and ecosystems. <italic>Managing the Commons</italic> is an admirably readable description of this effort which, in...

Evolutionary biology is above all concerned with the way life on earth and its setting change over time. The problem posed by Daily and Ehrlich, of how humans, the myriads of organisms that humans carry around in their bodies and the stage on which they interact have been changing over time, may...