In October and November of 2001, small numbers of soldiers from the Army Special Forces entered Afghanistan, linked up with elements of the Northern Alliance (an assortment of Afghanis opposed to the Taliban), and, in a remarkably short period of time, destroyed the Taliban regime. Trained to work with indigenous forces and personnel like the Northern Alliance, these soldiers, sometimes riding on horseback, combined modern military technology with ancient techniques of central Asian warfare in what was later described as "the first cavalry charge of the twenty-first century."

In this...