Desire lines are the paths we create that illustrate the tension between the built environment and the natural one, and how we relate to them differently.

Canberra author Felicity Volk had the concept of these gently compulsive pathways in mind when she began, some years ago, to write a story about a dysfunctional, but irresistible relationship.

She had finished the draft of her first novel, Lightning, which came out in 2011, and set out on another.

"I only wrote about 3000 words or so, and I knew that it was a story about these two people who are very compelled by each other," she says.

"It was dysfunctional love, truth and lies were one of the key motifs of that relationship, and I knew what the arc of the story was."

But it would be some time before those 3000 words - more angry missive than spark of a novel - would turn into Desire Lines, a sweeping love story spanning 60 years, and crossing oceans, from London to the Arctic Circle, but mainly cross-hatched across the journeys between Canberra, Sydney and the Blue Mountains. Evie and Paddy meet as teenagers in the 1960s, and though they have very different backgrounds, and set out on opposing life paths, their destination - each other - is the same.

The story - about truth and lies, our capacity for forgiveness, for self-deception, for endless love - is awash with metaphor, starting from the occupations of the two main characters. Paddy, coming from a place of trauma and abandonment, is an architect, working in the built environment. Evie, from a place of loving and nurture, is a landscape architect, coaxing the natural world through and around human artifice.

After their first teenage encounter, followed by years of silence and yearning, they reconnect as adults in Canberra. Paddy is working on the design of the new High Court in the 1970s, Evie on the surrounding landscape. From there, the love affair begins in earnest.

The story - those first few thousand words - was inspired by Volk's own complicated relationship at the time she first set them down. It was one that ended badly.

She had been living in Canberra for more than 20 years, working at the Department of Foreign Affairs, by the time Lightning came out. Her work was absorbing, and it would be several years before she was able to focus on writing again. After securing grants from the Australia Council and ArtsACT, she took a year off, and got cracking.

Her first novel explores the effects of bushfires on the Australian landscape and human psyche, and uses the metaphor of the necessity of fire as a force for regeneration. Desire Lines, conversely, begins in one of the very coldest places on earth, with Evie on a mission to deposit Australian seed specimens in the Global Seed Vault, buried in a mountain deep inside the Arctic Circle in Norway.

"When I was doing a little bit of research around floral species for that last scene of my first novel, somehow I came across the seed vault and I loved that sense of a baton passing between one novel to the next," she says.

"One finishes with fire bringing seeds into life, and the next begins with seed in ice, and the way ice preserves seed so that after a catastrophe, seeds can be used to regenerate, and it just appealed to me, that sense of seed again as metaphor."

Once she had decided on the professions of her protagonists, the central narrative was set.

"[It was] the way these two come together and that concept too of desire lines, the way the heart is compelled in certain directions regardless of what's laid out before it, that there are things that we just, for no good reason or against all sense, will follow a pattern and a line towards a destination and often it's a very circuitous journey," she says.

As is sometimes the case with desire lines - once they have been cast into the built landscape by forward-thinking architects who have had the good sense to wait and see where people are naturally compelled to walk before laying down permanent paths - Evie and Paddy's relationship looks doomed, or at least dysfunctional, from the outside.

Meanwhile, much of the novel is set in Canberra, against a real-life historical backdrop that takes the reader through some of the late 20th century's landmark events, including the grand opening of the High Court, and the government apology to Indigenous Australians and migrants sent to orphanages.

Volk says she chose to set the story in Canberra - and parts of it in the Blue Mountains - because knowing a place intimately is the best way to create a new world from it.

But she found during the writing, and her research into Canberra's early history, that she developed a deeper understanding of the city she had called home for most of her adult life.

"I think it is really hard to write place without being physically located within it, at least for a short period of time," she says.

"And then through the research about its past, you develop an intimacy with that knowledge in the same way that I was developing an intimacy of knowledge around Paddy's circumstances around what he grew from and into, and how that raw material shaped him. The same thing happens with a writer's relationship with place."

In plotting a plausible path between Paddy's life at Molong Fairbridge Society Farm School, to boarding school in the Blue Mountains, and thence to Canberra, she was making her own desire line.

"Once I had realised that the canvas was going to cover both the personal level and then the national level, again it worked as a really convenient metaphor to have the High Court as an emblem of truth-seeking and truth-telling, and then bring in the relationship that we have at that national level with the intersection of truth and lies, and finding a voice for our truths, and often that taking quite some time to achieve," she says.

Like her own writing process, the novel follows its own desire path, and as is often the case in life, her central characters have to go way off course to grow through and make their way back to where they started, or to where they were always meant to go.

"I ended up turfing that 3000 words I'd written - I saved one sentence, and it's a sentence that appears two-thirds of the way through," she says.

"That was about four years that it was just fermenting somewhere in the brain. And what was happening at the same time was that I had a different conception of the novel.

"It was written much more from a place of compassion and grace, whereas I think if I had written it that four years prior, when I was probably feeling a bit more grief-stricken, angry, embittered about this relationship gone wrong, I would have written a very different Paddy, and probably a different Evie as well, and the whole relationship would have been cast quite differently."