After my memoir, A Better Woman, was published a few years ago, people began to ask whether I had thought about my children eventually reading it. I suppose this was because of the memoir's frankness, and more specifically those sections which exposed the rage I felt towards my sons. "How do you think your son will feel knowing you once wished to smash his head against a rock?"

This set me thinking. Obviously it was an area I had examined before, both during the writing of the memoir and especially in the run-up to its publication. Then a friend started to run into trouble with a friend of hers, about the question of ownership of some material she wanted to use in a piece of fiction. What were the moral implications of writing exactly? Was there a sort of inherent imperialism involved in the act of writing? Did a writer have the right to use everything, or anything, that happened to her in her life when every life involves friends, lovers, family? While always convinced that I had the right to my own life, to my own "material" as it were, I started to ask myself some hard questions about what happened when my life was closely intertwined with someone else's. I began to read books by the relatives and children of writers: Margaret Salinger on growing up with J.D.Salinger, the daughters of the poet Anne Sexton writing about their mother's life and death, a memoir by the Canadian Alice Munro's daughter. Margaret Salinger wrote that her father had spent his life busy "writing his heart out" and that she was not convinced that the way he lived his life was well-balanced, or kind.

I went to the British Library and began reading about mothers and daughters, about infanticide, about rage. Whenever I begin a new book I read everything in a wild, haphazard way, sometimes only vaguely concerned with my emerging story. I knew I wanted to write about the relationship between writers and the world and, in particular, writers and family. Around the same time I was re-reading My Brother Jack (for no other reason than I often re-read my favourite novels just before I am beginning a new novel myself: it revs me up, raises the bar, shows me how far I have to go. The Great Gatsby, Madame Bovary, Jane Eyre, these are my images of perfection).

Who knows how novels arrive? Mine arrived, whole and at once, and I suddenly understood that I was going to re-write My Brother Jack and its sequel Clean Straw For Nothing from the female character Cressida Morley's point of view. In the Australian novelist George Johnston's famous trilogy, his fellow novelist (and fellow Australian and wife) Charmian Clift, is tranformed into the Cressida Morley character, all green-eyed beauty and subterranean silences. What if I wrote her version of the story? What would any story by Cressida Morley herself be like?

In the same way that F. Scott Fitzgerald transformed his wife Zelda into the shining Daisy Buchanan character in Gatsby and into crazy, beautiful Nicole in Tender Is The Night, Johnston transformed Clift, a serious writer, into a beautiful, betraying housewife.

The truth was more complex: Clift was dedicated to her work and always wanted to write her great book. She died without completing it but right up to the end her unfinished novel was there "like a owl on my shoulder". With two writers in the family, who owned the joint material? Who got to write the book? Here was a perfect way to write around my subject: the moral duty to one's family versus the moral duty towards one's work, the fall-out for children. Could I write Clift's broken book for her?

Like Sylvia Plath, Clift died by her own hand but, unlike Plath, suicide was not a leitmotiv throughout her life. Clift's strength, both as a writer and as a person, was her vitality, her great muscular joy in feeling the sun on her skin, the breath in her lungs, the transcendent beauty in a poem or a piece of music. She was for life, the way Plath was married to death, and even Clift's suicide at the age of forty-six fails to cast too long a shadow over her luminous prose. Soon, I was up and away. But soon, too, I realized that I didn't want my emerging book to be a literal translation of Charmian Clift's life ("She wasn't like that"; "She didn't do that"). Wasn't there more murky moral territory here too, stealing from the dead? And how could I possibly hope to emulate such luminosity? Co-incidentally, a biography of Clift appeared (Nadia Wheatley, The Life and Myth of Charmian Clift) which made me even more determined to create something new. (I didn't read the biography at the time but have read it since and can recommend it).

Eventually, I found myself developing an entirely new character altogether: the writer Katherine Anne Elgin. While she shares many biographical details with Clift, Elgin emerged as a character in her own right. She freed me up, allowed my imagination a wilder flight. Cressida Morley is still there, but she has always lived only as an invention.

Of course, much of Charmian Clift's background, and many of her preoccupations, happen to be strikingly similar to my own: journalism, expatriation, the on-going struggle between creativity and motherhood, the push-pull relationship with Australia. Greece, too, where Clift spent many years, also happened to be the place where I first started writing, where I began to unstitch myself, as it were, from my past. It was also the place where I got married for the second time, a country which has long exerted a pull over my imagination. I lived in Greece for a year when I was twenty: one of those periods in a life which stand out, still, and which I see now as acting as a kind of crucible in which my adult self was formed.

So, there you have it: life and art, art and life. After two years, the book was finally done and I was free.

Read an extract from The Broken Book here.