Martha C. Nussbaum has taken her transformative work as an academic philosopher into public debates about key questions of national and global political significance, making her one of the world’s leading public philosophers. Motivated by the desire to understand the conditions for well-being in light of the complexity of human existence, she has used the power of literature to reveal and explore the central place of the emotions: vulnerability, anger, and fear in moral and political life. A major theme of Nussbaum’s recent work has been the development of the philosophical foundations and practical applications of the “capability approach” to welfare economics. This approach provided a major impetus for the development by the United Nations of its Human Development Index (HDI), which takes into account not only income but also life expectancy and education. The use of the HDI has significantly shaped policy and practice around the globe. Nussbaum’s feminist commitment to the equality of women is evident in this, as in all her work.