The aim of this book is to offer an innovative agenda in the field of environmental economics. This chapter contributes to the conceptual and political understanding of this endeavour. It first states that environmental economics has to consider three fields: nature, justice and the role of time. To operationalize this claim, the chapter introduces and explains fundamental concepts such as entropy, joint production, ignorance, evolution, absolute scarcity, responsibility and homo politicus. These concepts are then applied using a historical example, namely the soda-chlorine industry, extending over a period of about three centuries. The lessons taken from this economic, environmental and political evolution are outlined. The concept of responsibility is then applied to address political aspects dealt with when examining the interplay between nature and economy. In an outlook, the chapter argues that these and other concepts do not form a hierarchically structured system. Instead, they are conceived as a network of interdependent concepts that reference each other but also remain categorically distinct from one another.