Between 1962 and 1975, I spent more time in Vietnam than in the U.S. and escaped under fire when Saigon fell. I speak the three languages of the country (Vietnamese, Chinese, and French). Although a civilian, I spent most of my time there on the battlefield, under cover as an enlisted man in whatever military unit I was supporting with signals intelligence. As a result, I was familiar with a good many of the battles Moyar depicts (and gratified that he noted the effect of monsoons on the fighting; downpours were often a deciding factor in the timing of attacks).

The period covered by the book, 1965 to 1968, was the time when the North Vietnamese stepped up their attempt to conquer the Republic of Vietnam (South Vietnam). The U.S. responded by bringing in ever-larger forces to counter the offensive. I’d been working in Vietnam since 1962 and brought my wife and child to live in Saigon in 1963; I evacuated them when things turned nasty in 1965.

The North Vietnamese continued to enlarge their forces in the south through 1968, when they launched three country-wide offensives, starting with the Tết Offensive at the end of January. The second set of attacks came in May with what Americans called “Mini-Tet.” The third wave was launched in August and September. Just how savage the North Vietnamese could be became apparent during their siege of the ancient city of Huế during the Tết Offensive. The communists rampaged through the city from January 31 to March 3, 1968. When friendly forces retook the city, they found 3,000 bodies. Another 2,000 people had disappeared and were never heard from again.

During the years covered by the book, both sides fought a war of attrition, hoping that losses would force the enemy to capitulate. But because of its huge battlefield casualties in 1968, the North Vietnamese decided to change tactics and emphasize guerrilla warfare. At the same time, U.S. forces, now under the leadership of General Creighton Abrams, shifted from large-unit search-and-destroy missions to pacification strategies.

One set of facts new to me involved the number of casualties on both sides. I was surprised to learn that the North Vietnamese routinely suffered far greater losses than the U.S. and South Vietnamese; the ratio was sometimes as high as 12 to one. In 1968, America’s casualties were 14,592 killed and 92,820 wounded; South Vietnam’s were 27,915 killed and 70,696 wounded. The number of enemy killed during that same year was said to be 181,149. The total U.S. killed during the war was 58,220; the U.S. Department of Defense puts the enemy dead at 950,765.

Also new to me was Moyar’s revelation that the North Vietnamese often cut off the fingers and ears of the American dead as souvenirs. Sometimes, they severed the dead’s genitals, too, and stuffed them in the corpses’ mouths. But U.S. troops were equally capable of bestiality. On March 16, 1968, a force led by U.S. Army Lieutenant William Calley Jr. attacked the hamlet of Mỹ Lai and killed between 347 and 504 civilians, including women and children, and raped approximately 20 women and girls. It became known as the Mỹ Lai Massacre.

Wisely, the author mentions “VC” or Việt Cộng (which means Vietnamese communist) only in passing. The communists themselves never used the term, yet it became American shorthand for those South Vietnamese — supposedly independent of North Vietnam — who opposed their own government. In fact, there were no independents. All Vietnamese communists were under the control of Hanoi. The war against the Republic of Vietnam was, in other words, strictly a North Vietnamese effort. The National Front for the Liberation of South Vietnam, sometimes called the National Liberation Front or NLF, was a propaganda fantasy dreamed up in Hanoi to persuade the world that the North Vietnamese invasion was really a local rebellion.

I was glad to see Moyar retell the story of the 1967 Battle of Dak To in the western highlands because that was one I was deeply involved with. The most intensive phase of the battle lasted the better part of a month and took a heavy toll. Americans suffered 283 killed, the South Vietnamese 61, and the North Vietnamese 2,188. When the fighting was over, however, no territory had changed hands.

(Moyar makes passing mention of the highlands’ red dirt. I know it well. When I was working in the highlands, I washed my clothes in the local water. It was infused with the red of the soil, and all my underwear came out pink.)

Despite the important role signals intelligence played in the war, those of us involved in intercepting the radio communications of the invading North Vietnamese were successful in hiding our work. Moyar only mentions my employer, the National Security Agency, once, noting our success in following North Vietnamese infiltration on the Hồ Chí Minh Trail through Laos and Cambodia. During the last four months of 1967, we counted a monthly average of 7,387 infiltrators.

The North Vietnamese fully exploited routes through Laos and Cambodia — including shipping weapons through the seaport in Sihanoukville — to infiltrate men and materiel into South Vietnam. The United States’ refusal to attack the North Vietnamese in those countries gave the communists an advantage that America never overcame.

Throughout the book, Moyar mines previously unavailable North Vietnamese documents for new insights. Those sources reveal, among other things, how deeply damaged North Vietnam was by U.S. attacks, especially the bombing campaign dubbed Operation Rolling Thunder. Conducted by the United States 2nd Air Division, the U.S. Navy, and the Republic of Vietnam Air Force from 1965-1968, it was intended to reduce the enemy’s capacity to wage war. By its end, some 30,000 civilians were dead, yet North Vietnam’s infiltration of the south continued.

We Americans serving in Vietnam were irritated (to put it mildly) by domestic press dispatches that denigrated U.S. involvement in the war. As Moyar reports, American journalists increasingly reflected the growing disapproval of the war among college students, literati, and hippies back home. By 1968, the anti-war movement was just starting. It ended up bringing the U.S. role in Vietnam to a halt.

Triumph Regained is the second volume in a trilogy begun in 2007 with Triumph Forsaken: The Vietnam War, 1954-1965. Moyar gives no indication of when the third volume will see the light of day. Once it does, I suspect the three books will be most useful to historians, researchers, and anyone else seeking microscopic detail on the war.

Tom Glenn, Ph.D., spent most of his 35-year government career assisting U.S. forces in combat with signals intelligence, first in Vietnam, later in other places that are still classified. Throughout, he was a civilian operating under cover as a member of the U.S. or friendly military unit he was supporting. He retired as early as he could 30 years ago to write. He now has six books and 17 short stories in print.