Sean McFate is the author of The New Rules of War: Victory in the Age of Durable Disorder, available now from William Morrow, an imprint of HarperCollins Publishers, and The Modern Mercenary: Private Armies and What They Mean for World Order. A professor of strategy at the National Defense University and Georgetown University’s School of Foreign Service, he served as a paratrooper in the U.S. Army’s 82nd Airborne Division and then worked for a major private military corporation. He holds a BA from Brown University, a MA from Harvard’s Kennedy School of Government, and a PhD in international relations from the London School of Economics and Political Science. He lives with his wife in Washington, D.C.