Chapter 1 of this book argued that moral philosophy should be based on seven principles of theory selection adapted from the sciences. Chapter 2 argued that these principles support basing normative moral philosophy on a particular problem of diachronic instrumental rationality: the ‘problem of possible future selves.’ Chapter 3 argued that a new moral principle, the Categorical-Instrumental Imperative, is the rational solution to this problem. Chapter 4 argued that the Categorical-Instrumental Imperative has three equivalent formulations akin to but superior to Kant’s formulations of the Categorical Imperative. Chapter 5 argued that my principle’s three formulations make it rational to adopt a Moral Original Position to derive moral principles. The present chapter derives Four Principles of Fairness from the Moral Original Position--principles of coercion minimization, mutual assistance, fair negotiation, and virtue—and unifies them into a single principle of rightness: Rightness as Fairness. Finally, this chapter argues that Rightness as Fairness entails a novel approach to applied ethics called ‘principled fair negotiation’, illustrating how the theory provides a plausible new framework for addressing applied cases including lying, suicide, trolleys, torture, distribution of scarce resources, poverty, and the ethical treatment of animals.