Roy started writing at the age of six, when her mother gifted her a notebook.
"It soon filled up with little stories, and she's the reason that I'm here now," said Roy at a session at the ongoing Jaipur Literature Festival here.
Her mother, much like Gayatri, one of the protagonists of "All The Lives We Never Lived", had to work hard to cater to her love of painting, culture and the arts.
It does not come as a surprise, then, that the novel is dedicated to her.
History and fiction blend into each other in Roy's narrative. Russian-born German artist Walter Spies, who was imprisoned on multiple occasions, accused of pederasty (perhaps because he was homosexual), and died in the sea during the Second World War, is a central character.
In the novel, Spies meets Gayatri, who runs away with him from her stifling marital home in the fictional town of Muntazir, whose name means awaiting impatiently for someone.
Both seeking a home in which they could be their unmitigated selves, they create the space they need in Spies' island home of Bali.
"To me, it's more important to stay true to the voices of the characters within the concert of voices in the novel," she said.
The risk of "inaccuracy" was, for her, worth it.
"Fiction is the space in which things happen that could have happened, even if they did not.
The desire to explore different lives is at the centre of both Roy's fiction and her values. She chose Spies as one of her characters after learning that he was Tagore's guide in 1927, on his trip to Bali.
"Tagore had in common with Walter the idea that nationalism should not be narrow patriotism, that curiosity for the world outside was fundamental and that the sense of humanity was far more important," she said, and ultimately, this is the vital difference between Spies and Nek Chand, Gayatri's intensely "patriotic and patriarchal" husband in the novel.
After all, as far as Roy is concerned, no matter what themes reviewers and critics unearth in her writing, her novels are and will always be "about people's ability to find common ground, without a language in common".