The Afghanistan Assumptions Project (AAP) is a unique, independent, scholarly, research-based project into the 20-year engagement in Afghanistan. The basis of the examination is seven fundamental assumptions—political, military, economic, cultural, and diplomatic—that drove U.S. policy in Afghanistan. Our research will be focused not just on understanding the mistakes made by the United States in Afghanistan but also on applying those lessons to future decision-making. Policymakers will not learn the necessary lessons from the war unless we are willing to look clear-eyed not at what the United States got wrong in Afghanistan but rather how it failed at specific issues, such as nation-building and counterinsurgency. The project also examines what the United States got right in Afghanistan, including education initiatives, health care accessibility, women’s empowerment, and building critical infrastructure. This project is engaging a broad range of experts, both in convening a steering committee of policy experts, involved in key diplomatic, political, and military aspects of the war, and also in conducting individual interviews with other policymakers, scholars, journalists, and civil and military leaders. The Center for Strategic Studies research will culminate in a series of white papers, journal publications, and a serialized set of articles for academic and policy communities examining which lessons learned from past mistakes can be applied to future strategic decision making by policymakers. In particular, the CSS team will investigate critical inflection points in the war in Afghanistan when policy shifted most dramatically, and address key assumptions made by United States policymakers and foreign policy analysts.