In the last decade, there has been an explosion of academic interest in health inequality. Although it is seldom stated explicitly, research into this area is inexorably tied to questions of morality and ethics. In this study, Yukiko Asada seeks to acknowledge the role that morality and theories of justice play in health inequality research, and to articulate the moral philosophy underlying this field of inquiry. Comprised of two distinct parts, Health Inequality first proposes a framework for measuring health inequality reflecting moral concern, then goes on to show how this framework can be applied to quantitative study. Using a specific time period as a case study, Asada questions whether or not health equity improved in the United States between 1990 and 1995. She suggests that the question of whether, and by how much, health inequity changed in the United States is dependent on the morality and accompanying empirical strategy used in the analysis. A unique blend of philosophy and quantitative research, Health Inequality will prove a valuable tool for academics and policymakers alike.