SETTING THE STAGE, the first of a new, ambitious 14-volume history of Vietnam and the war, is an important effort that is two decades too late. Better late than never, one can say coolly in a book review. In the meantime, partly because of the failure to know the story recounted here, the United States mounted a monumental and disastrous effort in which 57,000 Americans and 1.25 million Vietnamese were killed, and both countries suffered grievous political and social wounds from which they have not yet recovered.

Americans, who had had little experience in the area, went to war in ignorance of Vietnam's history. This was so not only for the public at large but also for many of the high officials making policy. And very few of the 3 million Americans who served in Vietnam over the course of the war ever learned much about the setting in which they had been placed, or the people with whom they were dealing.

Several retrospective studies of what happened have identified this as a crucial weak spot. Joseph Buttinger, once a strong partisan of the U.S. effort and a man who made prodigious efforts in the 1950s and '60s to remedy the historical void about Vietnam in the English language, wrote in 1977, "It has always been my contention that ignorance of Vietnamese history was one of the reasons the United States pursued a policy which, in its complete disregard of the political realities of contemporary Vietnam, was doomed to fail."

The same thought, backed up by inside experience, came from Paul M. Kattenburg in his recent, thought- provoking diplomatic history, The Vietnam Trauma in American Foreign Policy, 1945-1975 (Transaction Books, 1980). Kattenburg, who was the State Department's director of Vietnam affairs at the time, tells of returning from Saigon to an August 1963 meeting of the executive committee of the National Security Council. "I grew increasingly appalled as I listened to speaker after speaker, men at the top of the government like (Dean) Rusk, (Robert) McNamara, (Maxwell D.) Taylor and Robert F. Kennedy, who simply did not know Vietnam, its recent history or the personalities and forces in contention. I concluded that under such leadership, and given the extremely difficult circumstances in Vietnam, we would never be able to succeed there." Kattenburg blurted out that the United States should "withdraw with honor," and was slapped down and eased out.

While 500,000 U.S. troops were thrashing around in Saigon and the provinces, we were too transfixed by the crises of the moment, it seemed, to learn much about the underlying history. Now that it is all over, Americans are becoming interested in what really happened--or at least some people are betting bucks that there is an interest.

A 26-part television series, Vietnam: The Ten Thousand Day War, produced and originally shown in Canada, is scheduled to be broadcast on many American stations starting early next year. A book based on the series and carrying the same title is scheduled for publication in October.

Public Broadcasting has been at work for several years with French and British cooperation on a 13-part television history of Vietnam and the war, to be broadcast beginning in September 1982. The chief journalist on the project, Stanley Karnow, is preparing the print version, an extensive history.

Also in September of next year, U.S. News Books is scheduled to begin publishing its multi-volume political- military history of Vietnam, 1945-1975.

Setting the Stage , is volume No. 1 of The Vietnam Experience, the first venture of the Boston Publishing Co., which plans to sell its books mainly by direct mail over the next two years. The company claims that market tests suggest an "initial subscription base" of 100,000 for the series.

This introduction to Vietnam's history, geography and people is effectively written. Similar in size, format and overall presentation to the Time-Life histories of World War II, the book's many color photographs, old prints and graphic devices are a strong point.

In order to interest the general reader, the story begins at the end, so far as Americans are concerned, with a 20-page rendition of the fall of Saigon in 1975. Interspersed in the history are modern photographs and mini-essays on some of the modern consequences of historical trends. All this makes an attractive presentation, but also something of a jumble.

A curious omission in a book which has taken so much care and effort, and which is intended to be a permanent record, is the lack of footnotes or other sourcing for the information or even quotations in the text. This is disconcerting.

All that said, Setting the Stage is a worthy introduction to a long, tangled and unfortunate history.

Here is the story of the first 1,100 years of Chinese domination, from the conquest of 208 B.C. to the Vietnamese victory in 928 A.D., the early background to today's Sino-Vietnamese struggle.

Here is the history of Tran Hung Dao, who used underwater spikes to repulse Chinese invaders; Le Loi, who organized guerrilla bands and elephants in the anti-Chinese cause; and of Gia Long, who unified divided Vietnam and established the Nguyen dynasty. These great figures of Vietnamese history were known to most Americans during the war only as street names in Saigon.

Here is a full treatment of the history of French conquest and colonization. The French, who found Vietnam a country of landowning peasants and left it a country of landless peasants with an inflated and corrupt bureaucracy, may have doomed in advance all the frantic efforts of American "nation-building" in the 1960's. The book presents vivid details, in text and pictures, of what an 1885 French report described, fittingly, as "a true colony of exploitation."

Not least, here is the story of Nguyen Ai Quoc--later Ho Chi Minh--and the turn of events which brought to his Communist Party the leadership of the anti-colonial rebellion.

At every turn Vietnam was deeply affected by outside events over which the country had little or no control: dynastic cycles in China, the policy shifts of successive French governments, Japanese imperial ambitions and, eventually, the political tides in the United States. It is Vietnam's fate, as the text points out, to be too large and defiant to be swallowed but too small to secure its independence without depending on help from an outside force. This fact has had large consequences, whether the outside actor was Japan, the United States, China or the Soviet Union.

Setting the Stage does not address in comprehensive fashion the story of the American war, but it fulfills its title by describing a political and social terrain that was tailor-made for disaster. It is ironic and dismaying that this popular introduction to Vietnam should be published so long after the crisis is over for most Americans.

Given the late arrival of the United States as a central actor on the global stage, it is understandable that its people and even policymakers know little of the history of suddenly important places which are far away. But it is not excusable for ignorance to persist as involvement grows. One wonders, in this respect, where are the popular histories of El Salvador and Central America, of Angola and Namibia, of the Persian Gulf, to name a few? Will it take a new disaster to produce them? Will they, too, be 20 years too late?