In mid-1967, the North Vietnam leadership had started planning an offensive intended to win the war in a single stroke. Part military action and part popular uprising, the effort included attacks across South Vietnam, but the most dramatic and successful would be the capture of Huế, the country's intellectual and cultural capital. At 2:30 a.m. on January 31, the first day of the Lunar New Year (called Tet), ten thousand National Liberation Front...