Bill Shanahan was troubled by his line company duty in Vietnam: whenever his unit went on patrol, the North Vietnamese Army and Viet Cong could hear them coming. His unit didn't have a chance against an enemy that quietly emerged from the jungle like ghosts-and just as quickly disappeared. Shanahan wanted a better way to fight . . and to stay alive. And so, just four months after he arrived in Vietnam in 1968, he joined the LRPs (Long Range Patrol).The...