Hell on Earth : YOUNG MEN AND FIRE: A True Story of the Mann Gulch Fire, <i> By Norman Maclean (University of Chicago Press: $19.95; 301 pp.)</i>

This is a wonderful book about dreadful things. On Aug. 5, 1949, 13 National Forest Service Smokejumpers died trying to outrun a fire in Mann Gulch, near Helena, Mont. When Norman Maclean heard about this fire, he remembered his own youthful experiences as a Forest Service firefighter, and knew he wanted to write about it. But he did not begin this book until he was 74, after the publication of “A River Runs Through It and Other Stories.” When he died--two years ago, at the age of 87--he considered it unfinished.

In a sense it had to be, since the writing had become a process of self-discovery that sustained Maclean. “I, an old man, have written this fire report,” he says on the last page. “Among other things it was important to me, as an exercise in old age, to enlarge my knowledge and spirit so I could accompany young men whose lives I might have lived on their way to death.”

The Mann Gulch fire was a blowup, which occurs when a forest fire becomes big enough to generate its own circulation. A blowup is a tornado of fire, so hot that everything becomes its fuel; it can incinerate 3,000 acres in 10 minutes. It burns faster as it nears the top of a ridge, and this is where it caught the Smokejumpers--melting their watches, leaving bodies that had to be identified by dental work. This book is a long meditation on their last moments.

In “Black Ghost,” Maclean’s prologue, we get an idea of what we are in for. A few days after the fire, Maclean and his brother-in-law visit the still-smoldering Mann Gulch. There they see a deer drinking, hairless and purple and horribly burned. “It was probably like the two Smokejumpers, Hellman and Sylvia,” Maclean writes, “who did not die immediately and could never put out their thirst, drinking at every chance until they become sick to their stomach. . . . It must have been especially like Joe Sylvia, who was burned so deeply he was euphoric. . . . If it could have, it probably would have said, like Joe Sylvia, ‘I’m feeling just fine.’ ”

This is the most dreadful thing of all: For those who did not die at once--and there were two who didn’t--there was a kind of euphoria. Sylvia joked about his burns, although it was hard for his rescuers to laugh. That there is some euphoria in death by fire is the mystery which haunts Maclean.

This is religious thought, and it seems to me that “Young Men and Fire” is the clearest statement yet of what Maclean has been trying to tell us in all of his work: We are in heaven and hell, both at once. The boundary between the two is very narrow, and at any moment we may find ourselves altogether in one or the other. But God is merciful, if not always just.

I read this book with great anticipation, since one of my childhood ambitions was to become a smokejumper. In this I was influenced by the 1952 movie “Red Skies of Montana,” loosely based on the Mann Gulch fire. This movie filled me with the thrill of fire, which is a considerable thrill. Fire has been a constant in America’s history. There have been the Chicago Fire, the San Francisco Fire, the Peshtigo Fire, and only three years ago the smoke from the great fires in Yellowstone tinted the sunsets in Brooklyn, where I now live.

Maclean ridicules “Red Skies of Montana” for not sticking to the facts, but it seems incredible to me that it was made at all--with full Forest Service cooperation--since it does present some of the controversy that surrounded this tragedy.

When the foreman of the Smokejumpers, Wag Dodge, saw the inevitable end of the race between his men and the blowup, he set an “escape fire” and lay down in the ashes. The others--some veterans of World War II, but a green crew nonetheless--said “To hell with that,” ran on, and were overtaken 30 seconds later. Their parents later claimed Dodge was incompetent; that his “escape fire” had been the one that had burned their sons to death.

Maclean spent the last 13 years of his life reconstructing the fire: going back to Mann Gulch with two of the three survivors (Dodge died of cancer in 1955); establishing the exact points of death and escape; setting up models for the rate of combustion of such a fire, on such a day, in dry yellow cheat grass. In the end, he vindicates Dodge. There was no treachery, no betrayal. The passing of these young men was inevitable, given their chosen profession, with its heraldic goal of “taking on at the same time three of the four elements of the universe--earth, air, and fire.”

When I was writing my first novel, which is about tornado- chasers, I was often asked why anyone would want to do something so dangerous? Maclean answers this question as simply as it should be answered, and here he is at his best: “It is very important to a lot of people to make it unmistakably clear to themselves and to the universe that they love the universe but are not intimidated by it and will not be shaken by it, no matter what it has in store. Moreover, they demand something from themselves early in life that can be taken ever after as a demonstration of this feeling.”

Dreadful as these their deaths were, the courage of these young men and Maclean’s Homeric treatment leaves one with a feeling of exaltation. The doctor who examined their bodies tells Maclean that the young men fell, then rose and took a few more steps before falling again. “The evidence then,” Maclean writes, “is that at the very, very end beyond thought and beyond fear and beyond even self-compassion and divine bewilderment there remains some firm intention to continue doing forever and ever what we had last hoped to do on earth.”

Anyone who has watched a loved one die knows this feeling. So it must have been with Maclean, who labored on at this book through his last solitary years, often “thinking of my wife on her brave and lonely way to death.”