On the evening of Sept. 5, a crowd gathered in Brattle Theatre to hear best-selling novelist and Harvard creative writing professor Claire Messud discuss her latest work, “The Burning Girl,” with radio host Christopher Lydon. Organized by the Harvard Book Store and sponsored by WBUR-FM, Messud’s event sold out several days in advance––half an hour before Messud was scheduled to speak, a standby line of ticketless devotees stood waiting outside the venue for a chance at admittance.

Messud began the event by reading a passage from each of the novel’s three parts. Told from the perspective of 17-year-old Julia Robinson, “The Burning Girl” recounts the story of Julia’s friendship with a girl named Cassie Burns. Each of the novel’s parts details a different time in the girls’ lives, beginning from the hazily remembered origin of their relationship. The theme of knowledge and subjective truth, a topic Messud discussed at length following her reading, permeated each passage Messud read. “One of my preoccupations … [is the way] we tell stories in order … to resolve and cover over our uncertainties,” Messud reflected. “We think that we know people from this constellation of points … ‘I know that story, I know that girl … I’ve heard that story a thousand times.’ But actually, you never know that story.”

In “The Burning Girl,” Messud explained, Julia must grapple with what she knows and does not know to be true about her friendship with Cassie and its eventual end. “‘Cassie and I became friends in the second week of nursery when we were four years old. That was always the story,’” Messud read from her book, “‘though I can’t tell now whether I remember it, or have just been told so many times that I invented the memory.’”

Messud explained that obsession with knowing and not knowing has its roots in an experience Messud had as a child, when she relocated with her family from Australia to Canada, keeping in touch with her friends through mail. Thousands of miles away from her old life, Messud began to receive letters telling––in bits and pieces––of the death of an elementary school classmate. “[I was] haunted all my life,” Messud recounted, “that I only had those fragments [of information].” Decades later, Messud searched through digitized newspaper archives and was able to find articles covering her classmate’s death. When the official narrative conflicted with the details Messud remembered receiving from her pen pals, she began to consider more deeply the question of how certain truths come to be accepted as such despite the inherent subjectivity of human experience.

It was through this lens of memory and uncertainty that Messud approached writing from a teenage point of view. Describing “The Burning Girl” as “a children’s book for grownups,” Messud admitted that a great challenge she faced while writing the novel was creating content for adults while maintaining the perspective of an adolescent. However, she rejected the notion that a young narrator would be incapable of having adult thoughts or dealing with adult issues. “I’m a big believer in the complex realities of young people’s lives,” she said.

The event concluded with an audience Q&A session followed by a book signing, the line for which stretched across the room. Many of the attendees had long been admirers of Messud’s work, though some, like Lexington, Massachusetts resident Caroline F. Fitzgerald, were drawn to the event by the recent press Messud and “The Burning Girl” have received. “[Our book club] came primarily because … the feature on her in the Sunday New York Times magazine a few weeks ago really intrigued us about her as a person and author,” she said. “We feel the interview fell a little short of teasing that out of her. More about her personality, her process, the topics she might be interested in, the last question talking about her childhood and her mother and how she was raised in her family could have been an interesting conversation.”

“[This event] makes me want to read the book for sure,” Sabine B. Clark, another member of Fitzgerald’s book club, added.

Audience member Joyce Devlin, a Professor Emerita at Mount Holyoke College, left the event feeling similarly enthusiastic. “[Messud] has such an incredible vocabulary and her writing has such depth … I felt like I saw her thinking and her process, and I’m looking forward to reading more of her work.”