Contractualism has a venerable history and considerable appeal. Yet as an account of the foundations or ultimate grounds of morality it has been thought by many philosophers to be subject to fatal objections. In this book Nicholas Southwood argues otherwise. Beginning by detailing and diagnosing the shortcomings of the existing "Hobbesian" and "Kantian" models of contractualism, he then proposes a novel "deliberative" model, based on an interpersonal, deliberative conception of practical reason. He argues that the deliberative model of contractualism represents an attractive alternative to its more familiar rivals and that it has the resources to offer a more compelling account of morality's foundations, one that does justice to the twin demands of moral accuracy and explanatory adequacy.