This book explores moral responsibility, and whether it is compatible with causal determinism. Its author, K. E. Boxer, started out with deeply incompatibilist intuitions but became dissatisfied with the arguments that she and other contemporary incompatibilists marshalled in support of this view. Rethinking Responsibility has evolved out of her search for a more adequate argument. Boxer suggests that if incompatibilists are to be in a position to provide such an argument, they must shift their attention away from metaphysics and back to what H. L. A. Hart deemed the primary sense of the concept of moral responsibility, viz., the sense of liability. To say that an agent is morally responsible for an action in this sense is to say that she satisfies the necessary causal and capacity conditions for desert of certain forms of response. If incompatibilists are to show that among those conditions is a requirement for some form of ultimate responsibility incompatible with determinism, they must first clarify their understanding of moral desert and the moral responses associated with attributions of responsibility. The book examines different possible understandings of moral liability-responsibility based on different possible accounts of the nature of moral blame, the moral desert of punishment, and the relation between desert of moral blame and desert of punishment. A focal point throughout the discussion is whether, on any of the possible understandings, moral responsibility would require agents to be ultimately responsible for their actions in a way incompatible with causal determinism. Other issues discussed include what renders a defect a moral defect or a particular criticism a moral criticism, whether moral obligations are act-governing or will-governing, the connection between the moral reactive attitudes and the retributive sentiments, the relevance of the capacity to participate in ordinary interpersonal relationships, and whether it is possible to understand the moral desert of punishment in communicative terms. Boxer concludes that incompatibilists face an unenviable choice: either they must adopt an understanding of the moral desert of punishment that many find morally problematic, or they must abandon incompatibilism.