“We had been told nothing about Peter; my mother lived with such a sense of shame. It had been so well hidden. Then one day, my mother got on the phone and called us all, ‘can you come over, there is someone I would like you to meet’,” Ms. Olsson said. She had been a “wonderful” mother “but I think we all felt her grief in that there was something wrong and we didn’t know what it was. It was almost as if we weren’t enough and, of course, we weren’t enough, there was one of us missing.”

Ms. Olsson was journalist for nearly 20 years. In many ways, Pearl is her younger self. “I have given her a lot of the things about myself I really don’t like, shame, guilt, the appalling errors I made, some of the things I don’t even like to think I did are in Pearl.”

In creating Pearl, Ms. Olsson realized that she still had residual shame about herself as a single parent and her broken marriage — she married when she was 19 and had two children. “Everyone brings their whole history to everything in writing. Writing is mapping: times, emotions, your own blood,” she said. She is an active member of Sisters Inside, an organization that advocates for the rights of women and girls in prison. “I have a strong sense of wanting to rescue people as a form of atonement.”

Susan Wyndham, a former literary editor of the Sydney Morning Herald, described “Shell” as “one of the great Sydney novels.” Ms. Olsson’s writing, Ms. Wyndham said, “is like a prism that refracts dazzling images of the city, its politics and people, light and water and weather.”

In the last stages of writing “Shell,” Ms Olsson went on a writing retreat to a beach house in northern New South Wales with several novelist friends. She was struggling with the structure and ending of the book. “Even at that stage I was going nuts and thinking maybe I am not even close. I was cutting out and writing little tiny bits on squares and didn’t even have a title.”

As always she took refuge in walking, this time on the beach, where she picked up some shells.

“I took them back and put them on the table, and there it was, the Opera House. It wasn’t just the shape of the building. I could see everything else I was trying to work out.”

As it did for Jorn Utzon, nature provided the answers. You just have to look closely enough.