In this chapter I will elaborate the critique, introduced in the previous chapter, of some conceptual flaws in eco-Marxist theory. I argue for an extended application of Karl Marx’s insight that the apparent reciprocity of free market exchange is to be understood as an ideology that obscures material processes of exploitation and accumulation. Rather than to confine this insight to the worker’s sale of his or her labor power for wages and basing it on the conviction that labor power is uniquely capable of generating more value than its price, it is evident that capital accumulation also relies on asymmetric transfers of several other biophysical resources such as embodied non-human energy, land, and materials. The notions of price and value serve to obscure the material history and substance of traded commodities. This shift of perspective extends Marx’s foundational critique of mainstream economics by focusing on the unacknowledged role of ecologically unequal exchange but requires a critical rethinking of the concept of “use-value.” It also requires a fundamental reconceptualization of the ontology of technological progress, frequently celebrated in Marxist theory.