It is Maclean's story of his quest to understand the Mann Gulch fire of 1949 and how it led to the deaths of 13 wildland firefighters, 12 of them members of the USFS Smokejumpers.

In part 2, Maclean returns to Mann Gulch with the two living survivors of the fire and his research assistant Laird Robinson, himself a former Smokejumper.

On the day of the fire, Jansson was ranger on duty of the Helena National Forest's Canyon Ferry District, the area that included Mann Gulch.

Maclean started writing Young Men and Fire in his seventy-fourth year[3] and alludes frequently in the book to his age, both as a motivation and as a difficulty.

"[4] The book tells the story of an initially routine-seeming fire in which a combination of individually unlikely developments create an inferno in which most of the smokejumpers are killed.

In his foreword to the 25th anniversary edition of Young Men and Fire, author Timothy Egan describes Maclean as "trying to shape, or at least to see, art in tragedy while acknowledging that 'tragedy is the most demanding of all literary forms.

"[10] In the Washington Post Book World, reviewer Dennis Drabelle called Young Men and Fire "worthy of comparison to the masterpiece in its genre, Truman Capote's In Cold Blood".

[11] In USA Today, reviewer Timothy Foote compared the book to James Agee's Let Us Now Praise Famous Men.

Maclean stopped working on Young Men and Fire in 1987 due to ill health and left it unfinished at the time of his death in 1990.

[13] Thomas worked on it exclusively for months in the summer of 1991 while living in Saitama, Japan, distracted only by "the idiot barking of the landlady’s two miniature collies."

[16] A reviewer would later characterize "Black Ghost" as a "Shakespearean 'argument', or overture", that "contains all the elements of forest fire in general and Mann Gulch in particular".

[17] The book was published with a selection of photographs, including two by Peter Stackpole that originally appeared in an August 22, 1949, Life magazine feature on the Mann Gulch Fire.

[20]In the Los Angeles Times Book Review, William Hauptman wrote that "Dreadful as their deaths were, the courage of these young men and Maclean's Homeric treatment leaves one with a feeling of exaltation.

In an extensive 1994 essay drawing from her correspondence with Maclean, his friend and former student, the literary scholar and poet Marie Borroff, said of Young Men and Fire that "in the end it defeated him, at least in his own eyes....

"[39] "The poignant beauty of Maclean's prose is consoling", wrote the sister-in-law of Stanley Reba, one of the Smokejumpers who died in Mann Gulch, in a letter to the book's publisher: "I felt that at last they had not been forgotten nor would they be.

"[12] In 2014, the writer Kathryn Schulz published an essay in New York magazine reporting on a trip to Mann Gulch and revisiting Young Men and Fire from the perspective of climate change and evolving ideas about fire suppression: "Like many people, I went to Mann Gulch because of Young Men and Fire—because I had long loved it, but also because I had grown troubled by its role in the wildfire crisis we are currently experiencing.

But, like many such stories, it fails to ask the crucial question: whether that war should ever have been fought in the first place ... Today, the battle in Mann Gulch seems worse than pointless.