She was also a bestselling author who wrote under a pen-name and had legions of fans, selling thousands of books and living the dream life.

But, nearly 80 years after her death, Elizabeth von Arnim, publishing sensation of the early 20th century, is virtually unknown.

When Australian writer Gabrielle Carey first discovered her work, she was struck, above all, by them constant theme of happiness in her writing.

"So much of my reading life - which essentially means so much of my actual, daily life - had been spent reading miserable literature because, let's face it, most literature is miserable," she writes in the second line of her new book exploring the life of Elizabeth von Arnim - "a writer who wrote about being happy".

She wrote about it explicitly, too, rather than existentially. She was a writer who managed to pinpoint, and express, the things that made her happy, and to gravitate towards all those things even when the circumstances of her life seemed destined to steer her in the opposite direction.

She was, on the face of it, the most delicious prospect for a revealing biography, especially given that her large body of work has mostly been forgotten.

Most people haven't heard of Elizabeth von Arnim, not least in Australia, where she was born, but left as a child and never seems to have incorporated as part of her identity. A countess by marriage and a socialite by temperament, she was, by all accounts, a sparkling personality who published 20-odd books, almost all bestsellers, and had managed to live off the proceeds, while bringing up five children, having affairs and searching for a sense of peace throughout Europe in the early 1900s.

And yet, when Carey set out to learn what it was that made von Arnim tick - what her secret to happiness was - she found as many brick walls as she did alleyways, not to mention a couple of ready-made biographies that, frustratingly, gave little insight into her inner life. One of these was written by one of von Arnim's own daughters, who had every reason to burnish her mother's legacy and little incentive to delve deeper into her many complexities.

"There's no critical eye there at all," Carey says. "That's one of the things that inspired me to write it because the existing biographies just did not go where I wanted them to go. But it's not a traditional biography. I'm trying to get the spirit of the woman, I don't need to document every train trip and interesting sort of person she met along the way.

"She travelled so much, and met so many amazing people and she had so many incredible relationships. But there was something else in there that I wanted to uncover. I'm not sure if I found her at all."

Carey is known as a biographer and essayist, but her best-known work - the one with which many will always associate her name - is Puberty Blues, the teen novel she co-wrote with Kathy Lette in the late 1970s.

This latest literary quest, on the trail of a very different type of Australian woman, came about during a dark time in Carey's personal life, features of which illuminate the book as she learns more about her subject.

Von Arnim's story couldn't be more distant from modern Australian life, or from that of her much better-known cousin, the brooding - and tragic - modernist Katherine Mansfield. And writing about her life provided a welcome respite from the very modern woes Carey was experiencing at the time - a string of failed relationships, and a recent and prolonged incident of identity theft that left her bruised and traumatised.

After a trip to Europe on her trail, and to escape her immediate problems in Sydney, Carey accepted a residency at the Australian National University in Canberra last year. It was a situation she says had "no downsides"; she's a late-in-life convert to the joys of the national capital, and even now manages to find any and every excuse to escape here for the weekend.

Von Arnim, though, has proved a less conclusive, and more complex, source of satisfaction. Born Mary Beauchamp in 1866 at her family's home in Kirribilli, she spent most of her childhood and teens in London, where she studied music.

She would go on to become a headstrong woman who openly proclaimed happiness to be her guiding philosophy, and yet her life was filled with sources of what could just as easily, and understandably, have been misery. Unhappily married to a controlling Prussian count who expected no more of her than to be the bearer of his children, she was, unfortunately, particularly fertile. The couple had five children in quick succession.

She also had tempestuous affairs - with H.G. Wells and Lord Russell (elder brother of Bertrand Russell) - and, for most of her life, she railed against the expectations placed on women of her era.

"She's a complex character, and I think she would have been incredibly difficult to actually live with," says Carey.

And yet her writing, which was mostly satirical and fun-filled, was a refuge, not only for her but for her legions of fans and admirers at the time. Her many books were written under the pen-name "Elizabeth" or "The author of Elizabeth and Her German Garden", her debut novel and bestseller.

But unlike her cousin Katherine Mansfield, her writing is barely known today, even though her comedies of manners have often been compared to Jane Austen.

"It's really frustrating," says Carey. "I do touch on this in the book - her style went really, really out of fashion. We're still under the influence of modernism, really, and that's Katherine Mansfield. She's kind of cool, you know? I think fashion had a lot to do with it."

Comic writers from the period are also, today, deeply out of vogue which, considering the current craze for personal happiness and contentment - and the endless search thereof - seems at odds.

"I also think, with the literary world, they don't really take comic writers," Carey says. "But, as I hope comes across in my book, she's a serious writer as well. She just wants you to have fun while you're reading a book."

Yet in many ways, von Arnim was well ahead of her time, and would likely have no trouble fitting into today's fashion. Her life was hardly relatable - she had nannies, large houses and the resources to travel independently. But for all the opulence of her lifestyle - as a countess, but also as a successful writer who was able to build a 16-room Swiss chalet from the proceeds of her writing - she frequently longed for the simple life, to live in a cabin and swan around barefoot.

And - this was a lasting revelation for Carey as she read her journals - von Arnim paid close attention to the weather, and was frequently delighted by it.

"This is probably very fanciful of me, but I wonder whether that sort of down to earthness is something of her Australian character coming through," she says.

"People talk about there being an Australian style of feminism, and I think she was just so bold."