This book explains how and why the US lost the Iraq and Afghanistan Counterinsurgency Wars and the Vietnam War and sets out a proposal for winning the next insurgency, one field-tested on a small scale in Afghanistan. The author discusses his time with the US Army, first in Iraq as a member of the H.R. McMaster–led Governance Assessment Team established by David Petraeus. He then moves to his work with the 173rd Airborne in Afghanistan, describing the counterinsurgency program he developed with the 173rd and its early successes. The book concludes by reflecting back on the author’s earlier experience, asking the question, have subsequent events changed his views? Dennis de Tray is Senior Non-Resident Associate at the Center for Strategic and International Studies and Principal at the Results for Development Institute, Washington, D.C. .