Never before has the world experienced such significant progress in human development and at the same time seen such rapid and unpredictable changes in the forces that affect development. 700 million fewer people live in absolute poverty today than 20 years ago. The share of children dying before their first birthday is half of what it was in 1975. Since the collapse of the Soviet Union and the end of the Cold War, democracy has swept across developing countries. And today more developing countries are experiencing sustained broad-based economic growth than ever before. We at USAID are proud to be a part of this great progress. Our investments in health and education, support for agriculture and food security, encouragement of democracy and good governance, and assistance to governments in building capacity and encouraging private investment has helped build greater prosperity and stability, both for our partner countries and for the United States. But the forces affecting development are changing rapidly. Private-sector capital flows are seven times larger than what they were a decade ago, and now dwarf development assistance. The Arab Spring has ushered in new possibilities for democracy and growth in the Middle East, but also led to new challenges and uncertainties. Conflict and extreme poverty are increasingly intertwined. The growing success of many emerging markets has lifted millions from poverty, but also has unleashed much greater demand for natural resources, energy, and food. Climate change threatens to slow and possibly even reverse development gains in many countries. USAID and others working in developing countries must both embrace these changes and evolve with them in order to continue to be effective in supporting and sustaining development. Creating space to evaluate and better understand key development trends is essential to adapt to the rapid transformations in the development landscape. Rather than chase the latest fad or jump between shifting priorities, we must seize pivotal opportunities that we know can leave behind generational legacies of success. To that end, USAID is engaging with the smartest, most innovative, and most experienced thought leaders and practitioners from around the world to stimulate debate around key development challenges and opportunities. We call this effort Frontiers in Development. Designed to encourage forward-looking, provocative discussion and debate and to strengthen the analysis, design, and implementation of development programs, Frontiers in Development is aimed at cultivating innovative analysis and leadership to expand the Agency's learning and to increase our effectiveness. This collection of essays includes ideas from some of the brightest minds and best practitioners in development, some of whom you will be familiar with, and others you may not recognize. The essays include insights from people working in private, non-profit, and security sectors; from higher-income and lower-income countries; and from foundations, governments, and academia.