This is from an older answer of mine, updated with specific books:

The American historiography of the Vietnam War was established before the war ended and the fall of Saigon. Journalists, politicians, officers and other individuals that in one way or another had participated in the conflict on different levels started publishing books about the war, its causes and events out of a broad and political perspective. All of these books were with very few exceptions critical of the war and reflected the contemporary anti-war movement's view of the war as an unpopular one. Journalists such as David Halberstam (The Making of a Quagmire: America and Vietnam During the Kennedy Era, 1965, The Best and the Brightest, 1972) and Frances FitzGerald (Fire in the Lake: The Vietnamese and the Americans in Vietnam, 1972) wrote books that established what was to be known as the orthodox school of the historiography of the Vietnam War. The question that orthodox authors asked themselves came to be known as the central historiographical question: "Was the involvement of the United States in the Vietnam War justified?"

The answer to this question is and remains "no" among those who support the orthodox view on the Vietnam War. The involvement of the United States is characterized as a mistake and as a tragedy that should never have happened while the war itself is characterized as inhumane, immoral and that the United States never had a possibility to win the conflict.

In 1971 the Pentagon Papers, a confidential study on the United States involvement in the war between 1945 and 1967 and prepared by the Department of Defense, was leaked to American media that were quick to publish several articles based on the study. The Pentagon Papers played an important role in the development of the historiography of the war because it opened up the door for the revisionist school of the Vietnam War. What was to be known as the revisionist school was established at the end of the 1970s. Authors such as Guenter Lewy (America in Vietnam, 1978) opposed the orthodox view of the Vietnam War and argued that in the context of the Cold War, the involvement of the United States was justified and that the United States had legitimate reasons to help South Vietnam. Revisionist authors are just as critical as orthodox authors regarding the political and military leadership in how the war was led, but they do consider that there was a possibility for the United States to win in the conflict. Another important question for revisionist is the reasons for the defeat of the United States in the war, if the possibility to victory actually existed. Here, the classic revisionist thesis proposed by Lewis B. Sorley in A Better War: The Unexamined Victories and Final Tragedy of America’s Last Years in Vietnam (1999) argues that the US military fought with one arm tied behind their back and that the war could have been won. A more recent staple in the revisionist bibliography is Mark Moyar's Triumph Forsaken: The Vietnam War, 1954-1965 (2006).

This orthodox-revisionist debate has remained the strongest continuum in the historiography of the war, although the orthodox view has remained dominant amongst scholars and the general public. in the last decade, scholars that don't simply focus on the American side of the Vietnam War has started to question the relevance of this debate. The question that has remained so dominant has begun to be seen as something relevant only to those focused on the United States, seeing it as an America-centric question, without much relevance to the wider conflict. "Does it really matter whether or not the United States were justified?" "Does it really matter whether or not the United States could have won, seeing as they didn't and anything else would just be speculation at best?". The orthodox-revisionist debate only gave limited attention to the Vietnamese side of the war and although the revisionists were the first to properly start using sources in Vietnamese, they still focused exclusively on American matters. The attention that was given by both sides of the debate often resorted to broad generalizations and the use of western perspectives instead of South East Asian perspectives to understand Vietnamese ideology and perspectives. One of the reasons for this was that Vietnamese archives had remained closed since 1975 but although several books about the war, including general overviews and memoirs, were published in Vietnamese and that the People's Army of Vietnam released their own official history over the war (with all its flaws and biases), this material remained unused by researchers.

With the opening of Russian (and former communist bloc), Chinese, and Vietnamese archives throughout the 1990s, the historiography of the Vietnam War began to move in a different directions and perspective. The first was to make the Vietnam War international and focus on transnational and global perspectives from other countries besides the United States and how their involvement impacted the war and its progress. The other perspective is what the historian Andrew Preston has dubbed the "Vietnamese Turn". What this perspective brings to the scholarship of the Vietnam War is a place for the South and North Vietnamese side of the war. If they were represented in generalized terms before by historians and journalists that only had a limited training in Vietnamese history and culture, now those very same generalizations were being questioned and revised. Scholars began to highlight the South and North Vietnamese involvement that before remained in the shadow of the American, and to a smaller extent, soviet involvement. This was made possible by the extensive use of Vietnamese sources, sources that were now used to start asking questions with a Vietnamese perspective. Now both Vietnamese sides were shown as active participants instead of passive onlookers.

It is obvious that the orthodox-revisionist debate still takes a large and important place in the American scholarship of the war, especially if you consider the place that the Vietnam War has today in the historical memory of the United States. For these journalists and historians, the Vietnam War continues in the history books.

Sources:

"The Unending Debate: Historians and the Vietnam War" by Gary R. Hess, Diplomatic History 18:2 (1994).

"Rethinking the Vietnam War: Orthodoxy and Revisionism" by Andrew Preston, International Politics Review 1 (2013).

"Refighting Vietnam in the History Books: The Historiography of the War" by Phillip E. Catton, OAH Magazine of History 18:5 (2004).

"The Vietnam War as a Vietnamese War: Agency and Society in the Study of the Second Indochina War" by Edward Miller and Tuong Vu, Journal of Vietnamese Studies 4:3 (2009).

would it be unreasonable to conclude that the Orthodox and Revisonist schools were focused on what we should have learned, almost military history and the newer school is a more holistic, balanced and unbiased/unjudgmental discussion of what happened?