T. M. Scanlon is undoubtedly one of the greatest moral and political philosophers of our time. This volume brings together fifteen first-class critical essays on different aspects of his work, written by both early career and more established authors. The book consists of four thematically unified parts. The first part is a tour de force through Scanlon’s views on the nature of reasons and value. Essays in the second part engage with Scanlon’s moral theory, in particular contractualism and promissory obligations. The third part is reserved for Scanlon’s political philosophy. There we find a wide range of topics, from social and global justice to free speech and political neutrality. In the fourth part, several authors critically discuss Scanlon’s account of blame. Given the constraints of space, I will address the central arguments only of some of the essays I find important. The volume opens with Christine Korsgaard’s ‘The Activity of Reason’, in which she argues against the realist understanding of normative reasons Scanlon advances in What We Owe to Each Other (Cambridge, MA: Harvard University Press, 1998, hereafter WWOTEO). Realism about reasons is the view that reasons are mind-independent considerations that count in favour of or against some action, belief, or attitude. Most debates about realism revolve around specifying the metaphysical nature and epistemic access to such reasons. Korsgaard takes a different argumentative route. She claims that realists cannot explain why reasons exist and have claims on us. The problem as she sees it lies in the fact that realists ascribe a receptive role to reason, identifying it with the recognition of and response to substantive reasons (p. 4). Korsgaard argues that reason’s function should rather be conceived as active — in the sense of employing rational principles (hypothetical and categorical imperatives) — to pick out the reasons (pp. 4–6). Reasons then exist and have their normative force only because we, as rational beings who engage with the world in a certain way, exist (p. 12).