The contours of “sustainability” as it is being pushed by regulators and pulled by markets are beginning to sharpen in focus. The notion of “sustainability” has always had a tricky way of obscuring the hard questions like who or what is to be sustained, for what reason(s), and for how long. The broader the sustainability wave has grown, the more insistent the questions have grown. Yet, as Professor Malloy observes in Chap. 1 , the term’s use in the legal literature has remained almost haphazard. Part of our aim in convening the conference which lay behind this volume was to do a kind of fi tness check of sustainability as a regulatory program and as a set of corporate practices. But our deeper ambition was to assemble a team of people handling the beast in different quarters and with different tools—some not even explicitly or expressly concerned with “sustainability” as such—so as to tease out some commonalities of inquiry and insight in this fast evolving fi eld. What we discovered is that the distributed nature of legal authority in the modern, multi-agency state has made corporate and regulatory sustainability practices highly contextualized, adaptive, and yet still subject to some troubling failures and shortcomings. If we assume a standard defi nition of sustainability—the present’s fulfi llment of its needs without compromising the future’s capacities to do so for itself—the net to be cast in search of relevant corporate and regulatory actions is immense. Sustainability advocates have long noted several incompatibilities between the means and ends of sustainability within the modern, multinational fi rm and the traditional tools that command-and-control regulators wield. A single regulator cannot possibly stay current in all of the constantly improving knowledge domains needed to pursue “sustainability,” even to a fi rst approximation. Regulators, at least in the USA and EU, are possessed of jurisdictional authority stemming from legislation of limited scope, often limited to particular resources. (Turning an air pollution problem into a land or water pollution problem with a stringent permit is a ballyhooed form of regulatory failure.) Regulators, even those who seek only to push new technologies into a malfunctioning market for environmental controls, often lack the resources to improve their own standards in step with improving knowledge, engineering, and/or markets