This course has the ambition to provide students of the Postgraduate degree in “Economics of the Environment, Culture, and Territory” with an introduction to the plurality of schools of thought in economics that have considered the embeddedness of the economic system within a broader ecological system, and the requirements of sustainability as central concerns. After revisiting the historical origins of so-called ecological economics, the course distinguishes between the alternative theoretical, methodological, and ontological foundations of the various research programs that currently populate the sub-discipline, ranging from those located at the (mainstream) core of economics to those situated at the (heterodox) periphery. The course then illustrates how some of the most innovative approaches—i.e., those that most convincingly have questioned the assumptions of the orthodox perspective in economics and the resulting economic model—can help address the challenges posed by planetary boundaries, including the related need to rethink prosperity and incorporate social concerns into ecological economics.