Tim O'Brien, a contemporary American novelist and short-story writer of immense imaginative power and range, freely admits that the Vietnam War was the dark, jarring experience that made him a writer. In a 1993 interview (unpublished) he described the war as the "Lone Ranger watershed event of my life," and the time before his induction into the United States Army as "a horrid, confused, traumatic period -- the trauma of trying to decide whether or not to go to Canada." O'Brien went to Vietnam and served there in the Fifth Battalion, Forty-Sixth Infantry -- the U.S. Army's Americal Division -- from January 1969 to March 1970, patrolling the deadly Batangan Peninsula and the tragic villages of My Lai after the massacre there in March 1968. Unlike many of his peers, O'Brien returned to America sound of mind and body if not of spirit. He wrote of his war experience in a...