Like any historian worth his salt, Richard Bushman was determined early on to write about Joseph Smith's life "warts and all."

"I didn't want to cover up anything," he said by phone from his New York apartment. "I purposely sought to deal with all the problems, trying always to see things as Joseph saw them. I wanted to be empathetic, because that's what readers want."

Bushman's historical philosophy was strictly applied to "Joseph Smith: Rough Stone Rolling" (Knopf, 730 pages, $35), his work on the Mormon prophet. "I wanted to write a book in which Joseph could recognize himself.

"I once told a graduate student that I do it this way because I might meet this person in the afterlife. You have to write the book thinking the subject is in the room."

In fact, Bushman has written what is likely to be considered the definitive biography of Joseph Smith for many years to come.

"I liked the rolling part — a man in motion," Bushman said. "I also liked the rough stone. He knew he was rough and didn't pretend otherwise. I once wrote a book on gentility ('The Refinement of America'), and Joseph saw the artificiality of gentility. He didn't like Martin Van Buren (the U.S. president in the 1830s) because he was prissy and Joseph was rugged, and he felt more authentic."

Will the book be the definitive study of Smith? "It was the best I could do in the time I had — seven years. But I could have worked on the prose forever. By the time it was done, it didn't sound bad to me. I thought it was pretty much OK. My biggest reservations are that there are depths of Joseph Smith's thought I just could not reach. I hope the book works for at least one generation."

Bushman, who is himself a practicing member of The Church of Jesus Christ of Latter-day Saints, said he tried not to be "nervous in the writing.

"I don't try to rationalize polygamy or explain it. I just come at it head-on. I hope I give people courage to say that this is something we did — and God commanded it. And we don't do it anymore."

When asked about the balance of his work, Bushman said, "I'm not sure I want 'Joseph Smith' to be balanced. Prophets have a right to be wild. I want him to be a sculpted figure with distinctive qualities of his own.

"We are so sold on the genteel, noble kind of prophet that we forget about the Old Testament prophets. I take Joseph and I love the warts. None of his flaws stopped him from getting the job done. He was tremendously effective."