"A writer's mind is a very strange place," she says.

"It's a place that is very seductive for writers themselves, we can disappear into it for days at a time, there are people in there and things are happening but it's difficult for the people we live with.

"When I started writing I realised very quickly that it was all consuming for me. I was just absolutely taken by it, I would disappear for days and I knew instantly when I started writing that I was never going to stop, that I had discovered what I was supposed to do.

"But I was married to Michael, I had no plans of getting rid of him either so I had to make my imagined world meet my real world in a way and have them work together.

"I actually intentionally looked for a way to bring Michael into my mind so that I wouldn't have to come out of it so often."

Luckily for everyone involved Michael is a historian, his particular area of expertise is the extreme political movements of NSW in the 1930s.

"Basically I grabbed his history thesis and I found a novel in it."

The third wheel in their marriage is Rowland Sinclair the gentleman artist-cum-amateur detective who first appeared in A Few Right Thinking Men in 2010. This book was shortlisted for the Commonwealth Writers' Prize for best first book, the second in the series A Decline in Prophets won the Davitt Award for Best Adult Crime in 2011.

Now Rowland is off to Shanghai in All The Tears in China, the ninth book in the series.

"I wrote the first one thinking this is a way to lock Michael into my new career," she says.

"But what happened when I started writing it was I became fascinated with that era in history.

"We'd been married for 10 to 15 years by that stage, I knew it was his area of expertise but I hadn't paid a great deal of attention so I hadn't really encountered that period of history before.

"The 1930s are very under written, they're bookended by the very glamorous 1920s and the war and so they’ve been quite forgotten but in the 1930s all the emotions and the feelings and the tension and political polarisations were stirring which led us to World War II.

"As a period of time for a writer to examine why we do what we do and how the world hurtles towards disaster, it's been fascinating."

Gentill says it's also been frightening in a way, watching the world repeat the mistakes of the 1930s.

"The parallels are startling," she says.

"One of the things that always interested me when I started this series was how could civilised people find themselves in the Holocaust, in the situation where we did that, or how the world stood by and let that happen.

"Unfortunately, in a lot of ways, writing this series and living in the time that I do has made me realise how that can happen, how decent people can sit back and let atrocities happen, let things they know are unjust just go on because they're trying to deal with day-to-day life, trying to put food on the table, they're trying to deal with financial crises or just the ordinary things in life that demand our attention.

"The reality is as much as you would like to think that if you were in the 1930s you would have done something, that you would have stood up, led a movement for change, the reality is people in the '30s were struggling with day-to-day life like we are.

"It is so easy to put injustice on the back burner or to talk about it at the dinner table and do nothing because there are so many other things that demand our attention.

"What scares me is we know how the 1930s turned out."

Gentill lives in Batlow, near Cooma, with Michael and their two sons. Her stand alone novel Crossing the Lines won the Ned Kelly Award for best crime fiction in 2018.

"My husband will tell you I fall in love with every book I write," she says.

"I've just started writing the 10th Rowland Sinclair and it always feel when I'm writing Rowland that I'm coming home to friends.

"It feels very natural and relaxed to talk to him about what's happening, it does almost feel like I can sit in a room and talk to him. Yes, he is like the other man in our marriage but Michael has learned to live with that."

She doesn't travel to research her books, as she takes Sinclair around the world.

"I wish," she says, "it would be lovely if I was an author married to a merchant banker."

But then none of it might have happened in the first place without her personal historian.

All The Tears in China, by Sulari Gentill. Pantera Press. $29.99.