English by birth, Rubinstein has lived for the past 25 years in Australia, where her books and plays for children are extremely popular. The way she writes is, she believes, in large part due to her emigration and the loss of her cultural roots.
"I married an Australian," she says, "and rather gaily left England thinking that Australia would be just like home except sunny, and then I spent a long time thinking, 'What have I done?'" As a teenager, Rubinstein was always writing stories and poems and before leaving the UK she worked as a journalist and film reviewer, but once in Australia she wrote nothing for 10 years.
"As an adult migrant in a completely different culture and landscape, I think it took me that time to absorb it all.
"I started writing for children because through my own children I understood Australian children's culture much better than the adult culture."
Fantasy writing, says Rubinstein, was an obvious choice for someone not particularly confident in writing about a real-life culture.
Her first book, Space Demons, written in 1985, is an edge-of-the-seat thriller in which a group of children find themselves literally drawn inside a terrifying computer game, and then chased back into the real world by cybermonsters.
Rubinstein chose the subject because her son Matt, then 11, was mad about computers and spent hours zapping Space Invaders in arcades. "But," she says, "it was really just a device for getting into a fantasy world, an update on the enchanted forest."
And while the techno storyline is intriguing, the real attraction of the book is the children themselves. Rubinstein invests her 12-year-old characters with as much complexity and charisma as does many an adult novelist. She is unafraid of exploring the spaghetti of emotions that entangle children as they grow up and out of their families, and she has a tremendous sense of the things that matter to children and the different way they experience and respond to the adult world.
Although still fascinated by technology and the effect it has on our lives, Rubinstein is aware that it can cut us off from the physical and animal worlds which hitherto have been so important to children.
Foxspell, her heart-wrenching story of a young boy learning to cope with a new home and a family in crisis, is in many ways an antidote to the screen-bound world of Space Demons, plunging the reader into the smells and sensations of the natural world.
"Foxspell was me trying to come to terms with being a migrant," says Rubinstein. The foxes at the heart of the book are incomers, brought in cages on long voyages across the seas so that emigrant Brits could continue their hunting traditions on the other side of the globe. The setting of the novel is a hybrid landscape where imported ash trees vie with native species and where the fox has somehow adapted and flourished in an alien climate.
"It is a real place," stresses Rubinstein, "That's where my children used to play and where I walked my dog every day."
With subtle borrowings from Aboriginal myth, Rubinstein weaves a tale about guardian spirits and mystical transformations which can either be taken at face value, or read as the disturbed dreamworld of a boy dislocated from friends and family and trying to make sense of his world. On either level, the book is an affecting and engrossing read.
Rubinstein is a keen observer of family relationships, but her fictional families are not cosy safe havens which children can return to at the end of their adventures.
They are full of friction and drama, and often teetering on the brink of break-up. "I'm interested in the process of children growing up and away from their family. During the teenage years, families go through an awful lot of stress, but I'm also fascinated by the way families survive, how they reinvent and recreate themselves."
Her latest book, Under the Cat's Eye, combines technological intrigue with traditional fantasy, but again it is the relationships and characters that are the heart of the book. With an unerring ability to communicate the muddle of feelings and thoughts of the young teenager, Gillian Rubinstein is a marvellous chronicler of the process of growing up. "I love writing about families, " she says, "Maybe I should stop clothing them in sci-fi and just write about the people."
Gillian Rubinstein appears at the Edinburgh Book Festival, Charlotte Square on August 30 at 11.30am, and on August 31 at 1.45pm. Tickets 0131 624 5050.