Book excerpt: That the notion of “sufficiency” is essential for a good life is an idea that enjoys support across many ethical, philosophical, religious and cultural persuasions. This notion reasserted itself in the study of sustainability once modern society reluctantly took cognizance of the limited low entropy energy and matter available for human appropriation. There is today therefore a general recognition of (i.e. not necessarily wide agreement on the merits of or needs for) notions of sufficiency as a species of environmentalism within secular communities. In this context, a critical question that invites our attention is how to effect sufficiency, and in particular of dealing with the daunting challenge of injustice as well as questions of distribution within and between countries that it brings to attention. Given sufficiency’s original home, as it were, in tradition, the modern world has tended to dismiss it or to plead to individual voluntary simplicity when faced with evidence asserting its necessity. Sufficiency is also often written away as a spiritual problem. The domain of ascetics and the religious. How to habilitate sufficiency in a political economy for the secular modern facing its biggest existential challenge yet, in the form of the environmental crisis?