Afghanistan emerged as a significant U.S. foreign policy concern in 2001, when the United States, in response to the terrorist attacks of September 11, 2001, led a military campaign against Al Qaeda and the Afghan Taliban government that harboured and supported it. In the intervening 19 years, the United States has suffered over 22,000 military casualties (including around 2,400 fatalities) in Afghanistan and Congress has appropriated approximately $143 billion for reconstruction and security forces there. In that time, an elected Afghan government has replaced the Taliban; improvement in most measures of human development is limited; and future prospects of gains remain mixed. This book provides a framework for how to make a post-settlement Afghan state more effective in delivering equitable development and sustaining peace.