One of the most striking political developments of the latter half of the twentieth century has been a surge of concern for the natural environment. It is as if the great ecological awakening of this period constitutes a permanent watershed in the development of industrial societies: No longer will be it possible for governments, of any political persuasion, to take the natural environment for granted. After at least two centuries of unregulated exploitation of nature, this is surely, to all but a few self-interested corporations and their employees, a positive development.