This book is one of a pair of companion volumes devoted to the study of economic policies to enhance the quality of life. Our willingness to embark on so considerable a subject only reflects our conviction that economists as a body have already made sufficient headway on these problems to make such an undertaking worthwhile. We believe, in short, that this is a subject on which economists have a great deal to say that is useful; these books are intended both to bring that material together and to carry the investigation some stages further.

This volume is primarily theoretical and is consequently addressed to our fellow economists. However, it is not meant to be theory for theory's sake. Here our prime concern is policy; we are interested in the theory as a means of understanding the complexities of environmental programs.

The orientation of the other book is primarily empirical; there we will present and evaluate pertinent data and experience for guidance in the choice of policies for environmental protection and for the improvement of other aspects of the quality of life. Though it will be less technical than the theoretical volume and will consequently address itself to a broader audience, we intend it to provide the empirical counterpart to the theoretical structure developed in this book.

Our most direct debt is that to the National Science Foundation, whose support has made our work on the two volumes possible.