This book undertakes the first general assessment of ecological economics from a Marxist point of view, and shows how Marxist political economy can make a substantial contribution to ecological economics. The analysis is developed in terms of four basic issues: (1) nature and economic value; (2) the treatment of nature as capital; (3) the significance of the entropy law for economic systems; (4) the concept of sustainable development. In each case, it is shown that Marxism can help ecological economics fulfill its commitments to multi-disciplinarity, methodological pluralism, and historical openness. In this way, a foundation is constructed for a substantive dialogue between Marxists and ecological economists.