From her Melbourne home, Heather says the inspiration for Stories of Hope came after a bit of a drunken night in Slovakia.
"I was with my London based publisher [New Zealander Margaret Stead, daughter of author C.K. Stead] and we had spent the day in our apartment conducting research for Cilka's Journey," says Heather.
"We were staying in the same block where Cilka lived much of her life and people that knew her were coming to us and telling us her story."
Heather says she would ask the occasional question through an interpreter and the local people would open up and share their stories.
"Over drinks Margaret said she was flabbergasted at how complete strangers opened up to me," says Heather.
"She asked 'how did I learn how to listen', and I said my great-grandfather taught me.
"Margaret suggested that should be the next book."
Heather says as a young girl she would listen to her great-grandfather Christopher Charles Berry – a Pirongia identity and former mayor of the village.
She explores the skill in various chapters under such headings as Listening to your elders, … your children and … yourself. One chapter deals with a story about her brother Ian, told in his words with his permission.
The book title is inspired by the thousands of correspondence she has received, and people she has been invited to talk to in places such as prisons and drug rehabilitation centres, who say her books have given them hope.
"Hope is something we all need," says Heather.
Although currently trapped in Melbourne, Heather is working on her next fictional book, but that requires her travelling to Israel where she can do some more listening.
While in South Africa she received an email from a Canadian who said he had bought The Tattooist of Auschwitz when he was visiting his mother in Tel Aviv.
She saw the cover, with the tattooed arms, and said that must be about Lale and Gita.
This was a story Heather hadn't heard previously – three Jewish sisters who knew Lale and Gita, who also escaped with their lives, then had further hardships and ended up as freedom fighters.
Heather went straight from South Africa to Tel Aviv and met the two surviving sisters.
"They are amazing and beautiful women who believe they are ordinary people," says Heather. "That is my next book – Three Sisters."