What Sally Rooney is saying about her upcoming book 'Intermezzo'

Rooney said sibling dynamics and age play a role in the book about brothers.

Sally Rooney, the Irish author responsible for "Conversations with Friends" and "Normal People" is out with a brand-new novel this September. "Intermezzo" covers a more in-depth look at the relationships of two brothers and the romantic relationships they embark on.

Rooney discussed with The New Yorker in an article published Monday her decision to write about brothers and detailed how the characters of the new novel came to her as part of an interview with the magazine to discuss "Opening Theory," a short story drawn from "Intermezzo" and the highly anticipated new novel.

'Very much about the sibling dynamic'

While "Opening Theory" details how one character, Ivan Koubek, meets another character, Margaret, "Intermezzo" is a more in-depth look at the relationship between Ivan and his brother, Peter.

Rooney said the decision to focus on brotherhood was not intentional. "I can only say that I must have been interested in writing about brotherhood, since I seem to have spent several years doing so, but I can't explain why," she shared.

She said that she first began writing about Ivan before reaching a block. "I suddenly realized that Ivan had a brother—and, in that moment of realization, I felt I could see the brother's entire personality, and these other important relationships in his life," Rooney shared.

She said the book is ultimately about both the brothers and their partners. "It became a book that was very much about the sibling dynamic, as well as the various love affairs."

Age gap plays a role in 'rationalizing their family dynamic'

Rooney also shared that age plays a role in understanding the characters in her new novel.

"The age gap between them is never really explained—Peter is ten years older, with no siblings in between," she said.

Rooney said that each brother's age dictates how they perceive each other. "In a way, I think Ivan sees Peter as the epitome of adulthood, and Peter sees Ivan as a little boy," she said. "The more time I spent with them both, the more sympathy I felt for each of them, in their own ways of narrating and rationalizing their family dynamic."