Eleanor Catton on how she wrote The Luminaries

Creative influence can have a positive or a negative charge, either imitative ("I want to try that!") or defiant ("I want to see that done differently"). Both kinds of influence are vital for the health of an idea. Too defiant, and the idea will be shrill; too imitative, and the idea will be safe. For me, the moment when these two charges first come together – when I connect, imaginatively, something that I love as a reader with something that I long for as a reader – is the moment the idea for a story is born.

With The Luminaries, the positive charge came first. I have always loved reading books for children and young adults, particularly when those books are mysteries. Philip Pullman's Sally Lockhart trilogy, Robert Louis Stevenson's Treasure Island, and Avi's Beyond the Western Sea and The True Confessions of Charlotte Doyle are all novels that affected me powerfully: I read and loved them in a very different way than I read and loved other books. They were books that made me certain that I wanted to write, and I reread them not only with admiration but with gratitude and affection for having provided me with my life's vocation. (There are many books that I admire but to which I am not indebted, or for which I feel little affection. That kind of admiration, in my experience, does not create bonds of influence: it is not personal enough.)

From the very beginning I had an ambition for The Luminaries, a direction – but not a real idea. I knew I wanted to write an adventure mystery of some kind, drawing on all that I loved about books for children. I knew I wanted to write a book that was set in New Zealand – my first novel had not been set anywhere specific, and I wanted to know whether I was up to the challenge of writing a story firmly located in time and space. The west coast gold rush of the middle 1860s presented itself quite naturally: the west coast is a part of New Zealand I know fairly well, and a gold rush seemed a fine theatre in which to play out an adventure story. I started reading, beginning with gold-rush history, which led me to the nature of wealth, which led me to confidence tricks and scams, which led me to fortune telling, which led me to the stars.

I take a lot of notes when I read, particularly in this initial phase of research. I highlight everything I find interesting, and then type out everything I've highlighted, and then print out everything I've typed, and reread these printed notes as often as possible. In addition to non-fiction, I began reading as much 19th‑century fiction and crime fiction as I could, highlighting idioms, period details and ingenuities of plot. Most of the notes I took never made it into The Luminaries – at least not directly – but I could never have begun writing the novel without them. In many ways I see this initial phase as a process of accruing authority, of finding a perspective on the raw material of the future novel's world. I've always loved that "author" derives from the Latin augere, to increase.

This phase of reading and researching lasted for nearly two years, but it wasn't until the very end of it that the idea for the novel was really born. As a lark I had been learning to read Tarot cards, and I chanced on a copy of Italo Calvino's The Castle of Crossed Destinies, the plot of which is patterned on a Tarot spread. I found the book a terrible struggle, despite it being very slim, and, while struggling through it, I wondered why it was that novels of high structural complexity were so often inert, and why it was that structural patterning so often stood in the way of the reader's entertainment and pleasure. Did structure have to come at the expense of plot? Or could it be possible for a novel to be structurally ornate and actively plotted at the same time? I thought about the novel that I wished The Castle of Crossed Destinies had been – and this, at last, was my negative-charge influence, defiant rather than imitative, longed-for rather than loved.

I found a programme online that could track the movement of the planets through the constellations of the zodiac. I typed in the co-ordinates of the Hokitika gold fields, dialled the clock back to 1864, when gold was first discovered in the region, and began to watch the skies revolve. Over the next four years (of gold-fields time), I tracked the movements of the seven bodies visible to the naked eye over Hokitika's skies, wondering how I could turn the archetypes of the zodiac into human characters and a sequence of horoscopes into a story. Something caught my eye – a triple conjunction in Sagittarius, the house that Jung associated with the collective unconscious – and I knew I had a place to begin.