Long-run interactions between the economy and the natural environment are studied from all points of view. First, the aims of this overview are illustrated in Part I. Part II then explores and develops the concept of evolution, in particular distinguishing between evolution which does not involve the emergence of novelty, and evolution where novelty does occur. In Part III three types of time irreversibility are developed, and these concepts are used to show how time has been treated in the natural sciences, also typifying various schools of economic thought. Part IV is concerned with the economic modelling of these concepts. It extends and adapts neo-Austrian capital theory to provide a basis for the modelling of long-run economy-environment interactions. A heuristic simulation model is described, and its simulation results discussed. Part V draws some lessons from the earlier discussion and analysis. It also stresses the role and the importance of interdisciplinary work for the understanding of relationships between economic activity and the natural environment.