That Pat Tillman’s biographer would turn out to be Jon Krakauer now seems inevitable. Who else to chronicle the short, tragic life of the late NFL star turned U.S. Army Ranger than the bestselling writer who told the tale of Chris McCandless, the idealistic sojourner in Into the Wild? Or the accomplished mountain climber who offered his anguished personal witness to the 1996 catastrophe atop Mount Everest in Into Thin Air?

But Krakauer’s journey with Tillman’s story almost ran aground. It would prove to be his hardest book yet, with singular challenges, including two separate embeds with troops in the Afghanistan combat zone where Tillman was killed in 2004 by friendly fire from one of his fellow Rangers. The writing proved so daunting that the frustrated Krakauer fell far behind his deadline and got so “freaked out” that he withdrew the Tillman book from possible publication at one point. But part of what kept him going was the powerful voice of Tillman, who never publicly discussed his decision to leave the Arizona Cardinals for the Army in the aftermath of 9/11. Tillman’s widow gave Krakauer access to Tillman’s personal journals, and what emerged was a portrait of a complex, smart, sensitive, eloquent, and questing figure far different than the stereotypical hardass football jock portrayed in so much coverage of his life and death.

“He even had a copy of my book, Eiger Dreams, in his backpack when he was killed.”

Krakauer’s Where Men Win Glory: The Odyssey of Pat Tillman (Doubleday 416 pages $27.95) is a riveting examination of another American idealist’s startling path and haunting death, as well as a trenchant recounting of this country’s troubled course amid terrorism and war. Krakauer considers the dual narratives to be a risky approach, but says it reflects how he “wanted not just to write about Tillman, but put him in the context of his day and age.” In one of his few interviews discussing the book, the 55-year-old author spoke to The Daily Beast from his Colorado home.

What interested you in Pat Tillman as a book subject?

Tillman has always been on my radar as a PAC-10 sports fan who grew up in Corvallis, Oregon. I remember the Rose Bowl where he played for Arizona State. And like everyone else, when Pat Tillman was killed, I was blown away. I also thought, wow, there might be a book in this someday, but it was too soon after my Mormon book ( Under the Banner of Heaven) for me to consider it. But Tillman kept coming back to me. I was sure somebody else must have a contract to write about him, but one afternoon, I thought, what the hell. I sent off copies of my books to the Tillman family and got an encouraging response even from his mother, Mary “Dannie” Tillman (who later wrote a memoir of Pat Tillman entitled Boots on the Ground by Dusk).

What was the biggest challenge in writing this book?

There were so many. This was definitely the hardest book to research and write for me. It was challenging to get Tillman’s platoon-mates to talk to me. It was really challenging to be embedded with troops in Afghanistan for five months—that was an education for me, really hard. And the book turned into a big sprawling thing and I didn’t think that would happen.

Pat Tillman’s widow, Marie Ugenti Tillman, cooperated with you. How did that come about?

I first contacted Pat’s mother and she urged me to write to Marie, since she is his literary heir. She had his journals and letters and I would need her permission to quote them. But Marie is a very private, very wary person. I got a huge break when it turned out that Tillman liked my writing. He even had a copy of my book, Eiger Dreams, in his backpack when he was killed. He also liked Under the Banner of Heaven. That got my foot in the door with Marie.

Pat Tillman’s diaries add so much to your book. How did they change your view of him?

They do. Once Marie decided to cooperate in New York City, I stayed up all night, buzzed on coffee, making copies of all Pat wrote. Hearing his words was so powerful. I knew he was sort of a maverick and not a typical jock and football star, but I had no idea how complex he was, how sensitive or how liberal were his politics. God, I cannot imagine how Pat served in the war in Iraq that he thought was wrong, brought about by an incompetent president. And he could have gotten out of the Army after two years and returned to the NFL—I would have been out of there so fast! But Pat wouldn’t do it even though he loathed the war, was not happy in the Army, and felt guilt about how miserable he was making Marie. The journals show what an amazing love story there was between Pat and Marie. Marie did not talk about that, but Pat wrote about it extensively. It was very powerful and heartbreaking to me. Pat Tillman was a special guy, not just some jock constructing a different persona. He was the real deal.

What were the greatest lessons you learned from Pat Tillman’s life and the way he lived it?

There were a lot of them. That it’s not easy to be virtuous. That there is no guarantee that it will be rewarded. Also: Doing the right thing can be dangerous. And there’s probably no such thing as karma.

You made two reporting trips to Afghanistan. Why did you think that was necessary? Did you worry about your safety? What did you gain from that experience?

I never felt in great danger. I got shot at and I was in a Humvee that was blown up right after my ride. That was sheer luck. But I never really felt in danger, and I was never as frightened as I have been when climbing. But those months in Afghanistan were crucial for my understanding of the Army and how soldiers behave when attacked.

Did you investigate the various conspiracy theories that have swirled around Pat Tillman’s death, including the suggestion that he may have been murdered?

I investigated them all and, in every case, I realized there was nothing to them. If the Army wanted to kill Pat Tillman, they would not stage a complicated firefight like the one that claimed his life. They’d just have a CIA sniper dress like the enemy and shoot him. The Army couldn’t pull off something as complicated as what actually happened; it just never made any sense.

What are the similarities and differences between Pat Tillman and Chris McCandless from Into the Wild?

That’s an interesting question. They were both uncommonly idealistic. They were both pretty hardass in their ideals and sticking to them. But they chose such different paths—McCandless dropped out of society, while Tillman was all about living in this world and doing your duty. They were both very similar and very different.

Do you expect a film to be made of this Tillman book? And what did you learn from the film version of Into the Wild that will be helpful this time around?

I don’t know if a film will be made of this book. With Into the Wild, I pawned off that decision on the McCandless family. I proposed (and the family accepted) that I give the three of them (Walt, Billie and Carine McCandless) 75 percent of any money from selling the film rights to the book and keep 25 percent for myself. Additionally, I proposed that all four of us would have to unanimously agree on whether or not to even sell the rights and to whom—so that any one of us could veto a movie ever being made. In the case of the Tillman book, I proposed to Marie that she receive 75 percent of any money earned from selling the movie rights to the book, and that she have sole discretion about whether or not to make a movie, and who should make it. Marie agreed to this arrangement. I have no idea what she will decide. With Into the Wild, I really liked the film. I got lucky. I do not necessarily think that will happen again. Making a movie from a book is fraught with peril. I do know that Sean Penn (who wrote and directed Into the Wild) has talked to Marie and me about making a film of the Tillman book. I would certainly do another movie with Sean.

You do very few interviews for your books these days. And you don’t even have your photo on the book jacket anymore. Why is that?

Because I don’t have to (laughs)...I am doing more publicity for this book than I would like. But I have learned that if your picture is not on the book jacket and you’re not doing constant interviews, then it will pass quickly and fade away.

You have often told me in the past that Into the Wild remains your personal favorite among your books. Is that still the case?

It is. I have fond memories of the research and writing, plus I identified with McCandless. Into the Wild was also my first real book and will always remain a special book for me because it was written in a special time. I was more full of myself then, more intent on trying to be a stylish writer. Now, my writing is less slick. There’s just something about being young and full of yourself and trying so hard—I’m embarrassed by that, but also nostalgic for it. That was the only time in my life when I would wake up in the morning and be looking forward to writing. I never felt that way before, or since. I doubt I ever will again.

Plus: Check out Book Beast, for more news on hot titles and authors and excerpts from the latest books.

John Douglas Marshall was the book critic of the Seattle Post-Intelligencer until it ceased publication in March. He has interviewed Krakauer for Into the Wild, Into Thin Air, Under the Banner of Heaven, and Where Men Win Glory.