Many environmental damages are caused by substances which come into existence as undesired joint outputs in the production of desired goods. Whether an output is desired or not, however, is not an inherent property of the substance itself but depends on the context of production. This book studies the role of a potential ambivalence of joint outputs for the description and analysis of dynamic economy-environment interactions and for the design of efficient environmental policy. This is done in an interisciplinary way: methods and insights from thermodynamics, engineering sciences, economics and the methodology of economics are combined in order to develop an encompassing view on the complex and multivarious phenomenon of ambivalent joint production. By using the concept of joint production as a unifying framework for describing and analyzing the relations between human economic activity and the surrounding natural environment this book contributes to a critical and constructive assessment of the traditional environmental economic approach.