C.D.B. BRYAN is surprised that Friendly Fire has evoked such an overwhelming and enthusiastic response. He met Gene and Peg Mullen, the heroes of his book, five years ago, and instantly became fascinated and obsessed with the story of the death of their first-born son, Michael, in Vietnam in 1970, and their subsequent involvement in the antiwar movement. Bryan wrote 900 pages, decided he had used the wrong approach, and rewrote the entire book, all the while nagged by the conviction that there was growing in America an unwillingness to think about Vietnam, that his book, when it eventually appeared, would be met by an embarrassed and irritated silence.

Bryan, a tall Yale graduate who looks much younger than his 40 years, was in town last week on a promotional tour. He explained that he began receiving letters as soon as the first part of a serialization of Friendly Fire appeared in The New Yorker. Readers all over the country wrote that they had been moved to tears by Bryan's description of Michael clearing land with a tractor on the Mullen farm in Iowa the day before he left for Vietnam, the fumbling goodbyes in the local airport the next day, and the shock and horror six months later when Michael returns to the farm-country worked by his forefathers for over a century "in a U.S. Army issue twenty-gauge silver-grey casket."

"Reading about the Mullens made me glad that I engaged in some of the marches and some of the antiwar protests of the late '60s," a high-school English teacher from Chicago wrote Bryan. And, she added, in a theme echoed by others, "I'm ashamed that I didn't do more." A New York man wrote that Bryan's articles had "penetrated the confusion and shame which prevented me from thinking about the Indochina War." A woman from Pennsylvania wanted to write the Mullens; she explained that she had lost her job in part because she wore a black armband to work to protest against the war. Another woman from Montpelier, Vermont, wrote simply, "Thank you for the Mullen's story," as if the rage and frustration and sadness were understood, without the need for words.

Bryan deserves every bit of praise he will undoubtedly continue to receive for this book--for its sweep and beauty, for his faith in its importance which sustained him, and for the honesty which informs it. He is explicit: he writes that Friendly Fire depends on "the exploitation of Peg Mullen's grief" and he is ambivalent about that, as he should be. Bryan last week recalled a visit he made recently to a Western college where, to his surprise, the discussion centered around the "style" of the book. Bryan, a low-keyed person, blurted out, "Style is not what matters--this book is about people bleeding."

The Mullens bled, but they also fought. They were unsatisfied at the Army's official, terse and unfeeling explanation that Michael was killed by U.S. artillery, so they began to send off letters--to officials on all levels of government, to soldiers in Michael's outfit who were still in Vietnam, to others left with empty spaces in their lives by the continuing carnage. They placed advertisements in Iowa newspapers protesting against the war. Peg attended antiwar rallies, including the 1971 Mayday march on Washington, while Gene, more retiring, argued with local American Legionaries and doubters at the tractor factory where he worked the afternoon shift in addition to farming.

Bryan chronicles the Mullen's struggle, which soon consumed their lives, and reminds us of the horror of the Vietnam years. He quotes at length from the cold government form letters which responded with hazy platitudes to the Mullens' anguish. At one point, Peg resorted to a dictionary to look up the word "prolong"; she was trying to determine how long it took Michael to die.

The Mullens discovered the class nature of the war; Michael, who had been a graduate student in Agricultural Science (learning to improve crop yields to feed people in other parts of the world) when he was drafted, was an exception in an Army composed mainly of small-town 19-year-olds and the ghetto poor.

A BLACK SOLDIER who was in the trench next to Michael when he was killed wrote to the Mullens and gave them insight into their son's character. "I was the only Black in our squad," Private Willard Polk from Detroit wrote, "and I can honestly say I heard the word Nigger enough to last me a lifetime. You see, I could talk with Michael, he didn't care if you was Black or White. He was a good guy and we both had a great deal of respect for each other."

On their kitchen table cluttered with correspondence, the Mullens juxtaposed letters in revealing ways. General William C. Westmoreland wrote, "In Vietnam today brave Americans are defending the rights of men to choose their own destiny and to live in dignity and freedom." One of Michael's own letters said, in reference to the antiwar protest in the United States, "Most of the grunts (infantrymen), E-6's and below, are pulling that things get wilder at home."

The Mullens had the courage to make the juxtapositions and draw the necessary conclusions: they refused to take refuge in the warmth of Westmoreland's logic. That core of patriotism that exists in the heart of even the most hardened and bitter radicals did not prevent them from acknowledging that the war served no purpose, that Michael's death was not invested with the meaning concocted for it by comfortable liars in Washington. It is a hard and bitter truth, but the Mullens both accepted it--and acted upon it to save others from Michael's fate.

The Mullens confronted a smaller mystery wrapped within a larger and far more complicated one: How did Michael die? And why? Their natural suspicions, heightened by confusion among the responses to their voluminous correspondence, led them to conclude that the Army, in particular Colonel H. Norman Schwartzkopf, Michael's commanding officer, was willfully covering up gross negligence by the U.S. artillery unit which fired the fatal "friendly" shells which fell short.

BRYAN INITIALLY shared their suspicions, but after a series of painstaking interviews with all the participants in the action, he concluded that the Army's explanation did in fact hold up. Michael was killed because the artillery did not take into account the height of the trees on the hill on which his company was camped--a terrible mistake, but not a criminal one. Bryan is satisfied, but the Mullens, still suspicious, are not; as he explained last week, "They trusted me, and in some sense they think I betrayed them--that I became part of the coverup."

The end of the book produces a curious catharsis; Colonel Schwartzkopt himself turns to be an honest and increasingly bewildered man who performed well under trying circumstances. The effect of these somewhat unexpected revelations is to absolve anyone of the guilt for Michael's death, to mourn for him as another victim of a tragedy for which no one is ultimately responsible.

But there were in fact guilty men who must answer for the larger mystery the Mullens faced. Implicit in Friendly Fire is the understanding that Vietnam was more than a tragic mistake, an error in the limited sense that the shell which exploded in the trees above Hill 76 and killed Michael Mullen was an error. It defies logic to believe that the long years of blood and napalm were merely a tragic series of mistakes dizzily succeeding each other. Men, powerful, arrogant and lying men, plucked Michael Mullen out of graduate school and put him on Hill 76. The piece of shrapnel which snuffed out his life as he slept close by his black friend from Detroit merely completed a cycle started by others, far away.

The guilty in Washington contrast with the decent in Iowa--and elsewhere in the vast coalition of rage which formed the basis of the antiwar movement. Never before in history has a popular upsurge of such dimensions limited and eventually helped to end a foreign war. Bryan rightfully celebrates the movement's victories; amid the present lethargy it is well to remember that unprecedented numbers of Americans had the courage to challenge their deepest beliefs. An age of innocence has passed forever, and the liars will have a harder time of it the next time around. The Cold Warriors, as John Kenneth Galbraith wrote recently, are coming out from under various rocks and talking tough once again, but the Mullens cannot and will not listen.

Friendly Fire is about America; as Bryan remarked last week, "Perhaps the supreme irony of the book is that the Vietnamese do not even appear in it." Yet all over Vietnam, parents mourn their dead sons also. There is freedom and independence in Vietnam now, but there is also sadness and aching. There are stories of agony and courage which also must be told someday.

In a better world, Michael Mullen would have perhaps had the chance to become friends with his Vietnamese counterparts. The Vietnamese may well have understood the attachment of Iowans to the land and the rhythm of the seasons. Corn farmers and rice farmers might not have had much in common. But, then again, they might have.