Dave Eggers, the popular writer, editor and publisher, does good — and he does it well.

Students packed Sudler Hall on Tuesday night to see Dave Eggers and Valentino Achak Deng talk about Eggers’ new book, “What is the What.” The book tells the life story of Deng, one of the Sudanese refugees known as the Lost Boys of Sudan. Properly speaking, the book is a novel, but it is closely based on Deng’s actual experiences escaping from Sudan to a refugee camp in Ethiopia and eventually coming to America.

The friendship between Eggers and Deng started with a letter, Eggers said. In 2002, Deng was living in Atlanta with Mary Williams, the founder of the Lost Boys Foundation. Deng had been talking at schools about the atrocities committed in Sudan, but he wanted to tell his story in a more lasting form. He told Williams that he wanted to write a book.

“The only way I can succeed in stopping these atrocities and genocide from happening again is by telling the story,” Deng said.

Williams, who had read Eggers’ first book, “A Heartbreaking Work of Staggering Genius,” asked Eggers if he would write Deng’s story. After phone conversations, Eggers and Deng met at a basketball game in Atlanta and began the four-year process of recording Deng’s life.

In a Master’s Tea in Jonathan Edwards College on Tuesday afternoon, Eggers said that among the challenges he faced was the problem of how best to tell the story. At first, Eggers thought that it might be a book in McSweeney’s “Voice of Witness” series, a collection of nonfiction accounts from victims of human rights abuses. But as Deng and Eggers became better friends, Eggers soon realized that Deng’s story suffered from holes in the narrative, places where Deng’s memory failed him. Eggers decided to write a fictionalized account of Deng’s life, filling in the missing holes and assuming Deng’s voice in the first person.

“Valentino’s voice taught me how to write it,” Eggers said. “I was channeling him.”

The process was difficult for both writer and subject. Eggers called it “grueling” and “rarely fun,” and Deng discussed the emotional stress that accompanied his remembering and retelling.

“It was difficult for me to go back into years of agony and reveal the stories,” Deng said.

During the reading Tuesday evening, Deng’s cell phone went off three times. He apologized each time, and Eggers explained that many of the so-called Lost Boys from Sudan remain in touch with each other. On average, Deng gets calls from his friends once every hour, Eggers said.

Eggers and Deng emphasized the need to raise awareness — on behalf of Deng and the others who have escaped — about the atrocities that have been committed in Sudan since the 1980s. Deng said that when he first arrived America, he could not believe how few people had even heard of Sudan. Everyone knew about Egypt, he said, but few knew about its southern neighbor.

To help in the region, Deng has founded the Valentino Achak Deng foundation, which will build schools and libraries in Sudan. All the proceeds of “What is the What” — every dime, Eggers said — will go towards helping this organization.

English professor J.D. McClatchy called Eggers a “natural force of good.” Through organizations such as 826, a group of after-school writing and tutoring centers for children, Eggers has used his talents to help the community. And the “Voice of Witness” series from McSweeney’s has already published two books about human rights abuses in the United States.

Deng is currently enrolled in Allegheny College in Pennsylvania. He enjoys his studies there and is living the “college life,” as he calls it, which involves lots of studying accompanied by lots of partying on weekends. Apart from helping Sudan, one of Deng’s goals is to start a family.

“I want to get married, have a wife and kids,” he said. “And I’m working very hard on that.”

Although the novel took three more years to write than Eggers expected, it allowed him and Deng to form a valuable friendship, a mutual understanding that gave the book more depth.

“We worked as close friends,” Deng said, “and sometimes as brothers.”