“Oh, yes,” a retired NVA officer matter-of-factly declared to former U.S. Marine Otto J. Lehrack. “In the Que Son Valley in 1967, we killed more Americans than at any time or place during the war.” Road of 10,000 Pains, which takes its name from The Iliad, is an epic oral history of Vietnam's bloodiest campaign, fought for seven months in a...