His father, a creative type, was happy to oblige, and made up a story about a boy and his adventures with books. Or more specifically, with letters – the letters that formed the words that speckled the pages that he reads voraciously, so voraciously that eventually, the letters start to fly off the pages and into his eyes.

The story starts with a small boy hauling himself up some bookshelves, and being fascinated by a page, covered in letters, that falls from one of the books. Although he's yet to learn to read, he's fascinated by the shapes, and keeps the page, like a talisman, under his pillow. When he finally does learn to read, he does so fanatically, until one evening, he notices the letters leaving the pages and entering his own eyes. It happens everywhere he goes – street signs, books in the library – all are stripped by his devouring eyes, and he can't work out what to do. Eventually, all comes right again when he ruins a Christmas sign being drawn by a young boy, and cries all the letters back out of his eyes.

It was something of an adventure story, a suspense story, pitched at children and just scary enough to give them a thrilling jolt before all is resolved. Presumably, it did the trick, and Francisco – the teenager – grew up to be a healthy, reading, writing adult.

Decades passed, and by the time his father, Eduardo Castellanos, told someone else about the story, he was living in another country, far away from his now-grown children, and the world had changed.

But the woman he told it to was captivated. Diane de Castellanos, as she would eventually be, recalls being instantly enchanted by the story.

"It was just very different, and it appealed to my imagination – I could just see straight away," she says.

"To my mind, it was interesting and it was different, and it very definitely had a touch of Mexico about it."

Back then, in 1984, Eduardo and Diane were just months into a great love affair, one that would last until his death in 1999. She was a 38-year-old divorced mother of two girls, living in her childhood home in Narrabundah, and he was a 56-year-old Mexican diplomat, separated from his wife and living alone on posting in Canberra.

He had, as the story goes, spied her across the room at Juliana's, a nightclub in the basement of what was then known as the Lakeside Hotel – now QT.

He was besotted, and she was perturbed.

"I said, 'Go away, go away!' And he said, 'No, no, I'm not going anywhere!'" she recalls, laughing.

"He kept asking me to dinner and then gave me his card with his phone number, and said, 'Please, please ring me!' And I came home and I was huffing and puffing."

It was a neighbour – the same one who often looked after the girls while she was at work – who eventually persuaded her to give him a chance.

"She said to me, 'Don't be ridiculous, all you're doing is sitting here, night after night after night, on your own,'" she says.

"He just wants to take you to dinner, Di, he doesn't want to marry you! Don't be so stupid."

Four years later, the two were married – at the Lobby, of course, where else? Shortly after the wedding, they returned to Warsaw, where he was on his last posting.

It was, she remembers, a beautiful and exciting marriage, even after they returned to Canberra to settle down for good.

Eduardo was first and foremost a painter – of bright, dramatic canvasses, many featuring the vivid iconography associated with his homeland. Born in Santa Maria del Rio, he had studied at the National Institute of Fine Art – La Esmerelda – in Mexico City. He became a professor at the institute, and wrote extensively about art, until the mid-1970s, when he changed careers and began life as a diplomat. His first appointment was as cultural attache at the Mexican Embassy in Quito, and later travelled to Brussels and Rome before fetching up in Canberra.

But painting was a constant presence in his life.

"He used to come home from work and paint in his suit," says de Castellanos.

"He had the tidiest studio I have ever seen in my life – it was spotless."

He was also a great conversationalist and a charismatic storyteller – an elegant and captivating figure who, with his flamboyant Spanish accent, charmed everyone he met.

But the story of the Devourer of Letterswas placed firmly on the backburner, despite de Castellanos urging him, periodically, to turn it into a book, even organising to have it translated into English.

Although he never got around to publishing the book, Eduardo worked until the very end, creating a portrait for their anniversary just months before he died, at home, of cancer.

That was 16 years ago, and de Castellanos, an accomplished artist herself, has lived with his memory and his influence on her life ever since.

"Occasionally, the odd person will suggest, 'Why don't we set you up with somebody, Di?' And I say, 'No, no,'" she says.

"There wouldn't be much point anyway – they'd walk in here and get the message straight away."

The house – a muted and gorgeous treasure trove of artworks and objects collected in markets and shops throughout their overseas travels – is filled with portraits of Eduardo. He used himself as a constant study, and she likes to be able to turn and see him from almost any vantage point – even if it's via the lavishly painted kitchen cabinets that he created for her "on commission", or the cloudscapes and still-life paintings interspersed with the great, colourful canvases.

It's a constant work in progress – Diana confesses that behind the canvasses the walls are pocked with holes from all the picture hooks that are endlessly being shifted. She has much of her own work arranged on tables and shelves as well – dolls and clay figures, embroidered toys and meticulously crafted objects that are simultaneously beautiful and faintly disturbing. She has no formal training, but an artist's finesse and a compulsion to create, something Eduardo was careful to nurture throughout their marriage.

"He kept urging me on, and I guess I had more confidence when he was around," she says.

"He kept telling me, 'Stop making pretty things, anyone can do that. Think.'" The results would often perturb her daughters' friends, who wondered, sometimes aloud, whether she was "troubled".

But through the years, she has never forgotten the strange, quirky story of the Devourer of Letters, and has finally managed to turn it into a book, with the help of her much more technically literate daughter Katina, and the online self-publishing house Short Stop Press.

Rendered in fine calligraphy and illustrated with her own intricate drawings and collages, The Devourer of Letters is now available online as an e-book.

She says she was relieved, after sending it to so many publishers, to finally get a positive response.

"When [the publishing agent] read it and got in touch with me, she said, 'Oh my God, I was so relieved when all the letters went back into the books!'" she says.

"I said to her, 'Don't you think it's a little bit scary?' And she said, 'Kids love to be scared!'"

The illustrations – completed on the fly after she sent in one and the publisher asked for nine more – have an unmistakeable tinge of Mexico, although de Castellanos worried about going over the top in emulating her late husband.

"I just felt a really huge obligation to do it properly. I thought if I'm going to do this, I can't muck it up," she says. She even penned a dedication, on behalf of Eduardo, to the book's original target, Francisco, with whom she's no longer in touch, and hopes she can one day get a hard copy to him.

And she's confident Eduardo himself, always so adamant that she stay true to her own artistic vision, would be pleased with the results.

"I think he'd be smiling," she says.

The Devourer of Letters is available as an e-book on Amazon and at shortstoppress.com.