It is a "terrible" book — and it is flying off the shelves.

In less than a month after its release, Oxford University Press is in its fourth printing of "Massacre at Mountain Meadows" by Mormon authors Ronald W. Walker, Richard E. Turley Jr. and Glen M. Leonard.

The three authors present a dark chapter of Utah history where a band of LDS militia members — aided by Indian allies —  killed a party of California-bound emigrants, including more than 120 men, women and children.

In a recent interview Walker, Turley and Leonard admit their book is terrible — not in the quality of its writing nor in its scrupulous accuracy, but because reading the book brings the reader face-to-face with the horrific acts it chronicles.

"You can't do it any other way . . . If it is a terrible story, you can't put pastels on a landscape like this," Walker said.

"It's a difficult book to read — and yet you don't want to quit reading it, because . . . you want to see if something does happen to stop it, but you know it won't because you know the end from the beginning," Leonard said.

"And yet, by going through that emotional witnessing of what happened, you begin to learn what really happened and learn whatever lessons can be gleaned from it," Turley said.

The type of book that was published a few weeks ago is not the same as what the authors intended to write when they began the project about six years ago.

"Wasn't this a two-year project?" said Turley. "It was a six-month project!" Walker said.

Originally the authors saw the book as a collection of essays that each one of them would write. As they progressed they realized the subject deserved a narrative. It was a story that needed to be told.

"We also found a lot more information than we expected," Turley said. "We did research from New England to Southern California, the Pacific Northwest to the Southeast. A lot of time was spent in the South Central states where a lot of the victims originated. And then months of time, cumulatively, at the National Archives. And the total amount of information we brought back from that was daunting. It took years to go through that information."

"It became not just a blessing of riches, but a mixed blessing of riches," Walker said. "Which is to say it became very hard to get our hands around all the information and still tell a very, what we hoped to be, a concisely written narrative that would interest the general reader."

Maintaining a high standard of scholarship while creating a tightly written narrative was a difficult task. "The general rule that most (historians) use is that a quarter gets stripped out before the final draft. But in this case I think there was a lot more than that," Walker said.

"And we agreed as we began to work together that we would not be disappointed if some favorite page or part of a chapter we wrote was on the cutting room floor, because we recognized as we were writing we were getting more information on the page than we could use. We had to trim it and set some priorities that would make the book tell the essential parts of the story without loading the reader with too much detail or too many asides," Leonard said.

"Which is why we reduced a lot of the detail to the back matter, where people who are really interested in that finer detail could find it without burdening every reader with that responsibility," Turley said.

The process was collaborative and intensive. The authors met regularly and went over each intricate detail.

"We know as we went along we were watching each other change positions on various matters. As one would do a draft, we would chew on it and have to be convinced that what he was writing was something we could support. We would do our own research and come back and say, 'I think I am leaning your way,'" Leonard said.

The pieces of the puzzle did not fit together easily. The authors set strict historical standards on how to approach information.

"We made a very concerted effort to let the information tell the story and to write, not just for an immediate audience, but write in such a way that time would validate our conclusions," Turley said.

"Some who read it said, 'I understand it now. I understand it now,'" Leonard said, "And it is an understanding that you can accept, not one where you go away wonder if (the authors) got it right. It makes sense. It just falls together."

But they do not expect everybody to agree with their conclusions. They recognize that every reader brings to the book their own point of view. A person who is inclined to trust the authors and shares their worldview will have a different experience than someone who does not.

"And I'm not so sure we expect those with a radically different point of view to accept what they read. How can they?" Leonard said.

"But we do invite them to assess our sources," Turley said.

"And every sentence and every paragraph," Walker said. "Because we weighed every sentence and paragraph as we wrote."

That writing had its affect on the authors.

"It changed us all physically. Aged us," Walker said.

"Out of proportion to the amount of time spent," Turley said.

"There is (also) a change within as you see, as you look at this . . . wishing that these people had more patience and tolerance and forbearing and hoping that you can have that as well in your life. So I think there is an enriching aspect of this horrible tragedy," Walker said.

The authors explained in the preface to the book that their research divided into two areas. The first area, the committing of the crime, is covered in "Massacre at Mountain Meadows." The second area covers the aftermath of the massacre or "punishment" and will be the subject of a future book.

"A substantial amount of work has been done on the (second half of the) story," Turley said, "and we say in the preface that we are going to leave it for another day. As you know . . . we badly missed our estimate on when we would get this book done. So we are very loathe to commit to any deadlines on when the second volume will be done."

"We'll promise you you'll see a volume two," Walker said.

Meanwhile, Walker and Turley will guest edit a special issue of BYU Studies on the Mountain Meadows Massacre. The issue will feature a selection of affidavits, interviews and other primary sources used in writing their book.

Read more about the Mountain Meadows Massacre:

Part 1: 'Massacre' authors want readers to ask questions

Part 2: Writing 'Massacre at Mountain Meadows'

Part 3: 'Massacre at Mountain Meadows' shows dark episode