But the first-person aspect of Mountains Beyond Mountains is more than an insurance policy on the book’s credibility. The work also contains passages exploring the enthusiasm and ambivalence Kidder felt as he watched and heard Farmer outlining the world’s inequities in the starkest and most accusatory of terms.

“The point about someone like Paul and his group is not to feel envious or to feel diminished by them,” Kidder says. “But it’s inevitable, we’re human, you will feel that way.”

By honestly reporting his own reactions in the book, Kidder says he aimed “to acknowledge the kind of discomfort that one’s bound to feel from time to time in the company of a guy like that”—to make his book truer and fuller than “a campaign biography.”

“I just had to acknowledge that it would at times wear on the reader,” he says. “It has the advantage of being true, and it would clear away those shallow discomforts.”

He also describes instances where he challenged Farmer’s inflexible idealism and doubted the man that many say is perfect. (Kidder dutifully records just how Farmer won almost all of their intellectual debates.) The pair, as Kidder tells it, are in nearly constant dialogue—and, towards the end of the book, something like conflict.

Writing a book on someone is “an odd basis for a relationship, for friendship,” Kidder says. “I’m not sure I’d let anyone do this to me.”

Farmer, too, has had his share of discomfort in connection with Kidder’s book—some of which showed through at a recent event the two held together at Longfellow Hall, sponsored by Harvard Book Store.

In between Kidder’s readings of excerpts from Mountains Beyond Mountains, Farmer—always smiling—tossed barbs the author’s way, repeatedly mocking Kidder’s educational pedigree of Andover and Harvard. Farmer also wryly announced plans to retaliate by publishing his own multi-volume version of the months he and Kidder spent together, including such installments as Cry, the Beloved Tracy. Playing on the titles of Kidder’s most laurelled works, he joked that he would publish more books about Haiti: Hut for Kidder’s House and Slum for his Hometown.

Still, the conflict has never crossed into outright hostility; Farmer echoes Kidder in calling their relationship throughout the research and writing process as close. “He’d be the first to admit, I suspect, that I’m a friendly person and you don’t hang around with someone for years and not become friends,” Farmer says. “Particularly if you’re talking a lot and living through dramatic experiences together.”

But none of this, Farmer says, could change the fundamental oddness of having a prominent author scrutinize his life while he was still living it.

“I pretty much interact with people, all people, in a limited number of ways,” he says. “People are either my patients, my co-workers, my students, or my family—or some combination of the above. Tracy was different mostly, I think, because he wanted to be different.”

But Farmer says he knew little of the internal dissension Kidder felt until after the research was over—and indeed, he says that several of the arguments and verbal fights Kidder narrates had gone unrecognized by him at the time.

“I wasn’t really aware that I got on Kidder’s nerves sometimes until I read his book,” Farmer says. “I knew that I was running him ragged, and that our travel styles didn’t match at all, but I learned more about what he was thinking when I read his book, which was pretty recently.”

Seeing Mountains Beyond Mountains for the first time—after the book was complete save for the fact-checking process—was a wrenching experience, Farmer says.

“The first time around wasn’t all that pleasant,” Farmer writes in an e-mail. “I mean, I laughed, I cried, and all that. But it’s very strange to be the topic of a book (I’m not even dead yet! I’m 43 years old!). And although the facts seemed right, and he caught wonderful things that I’d forgotten in the mad swirl of everyday work, I didn’t savor the book on round one. It scared me.”