Four decades later, this awareness of different worlds, and of the multiplicity of worldviews, is a crucial factor in Smith's own diplomatic career.

That, and his way with a guitar. Smith is now well-known for his parallel career as a singer-songwriter, who "writes about love and war zones", and engages with tribal leaders in dangerous war zones while he's at it.

Once described as "Australia's secret weapon" in international diplomacy, he was the first Australian diplomat to be posted to Afghanistan's Uruzgan Province in 2009, an experience that he turned into a highly acclaimed album of songs, Dust of Uruzgan. But it wasn't until after his second, shorter stint there in 2013 that he got an inkling there might be a book in it. Or rather, a publisher approached him after a performance, and suggested he think about putting his experiences on the page.

In fact, Smith already had a lot of pages filled by then. A born scribbler, he had long got into the habit of recording his experiences.

"Afghanistan is this two feet here," he says, motioning to the shelf full of bound A4 notebooks on a shelf in the bright, messy study facing out from his O'Connor home.

"It's everything from song lyrics to little anecdotes to meeting reports to briefings. I'm a scribbler, literally - you wouldn't be able to decipher it."

He's been keeping a diary since he was in his late 20s, mainly for song-writing, but the latter years of his diplomatic career have been too interesting and rich not to record, for the sake of his memory if not exactly for posterity.

But still, a book looked too much like hard work from where he sat in late 2013. His wife of 12 years, Maryanne Voyazis, was about to have their first baby, and in the meantime, Smith had built up a spoken word show to accompany his songs.

"I wanted to take it out of the pub and into blackbox theatres, so I built this show with photographs that ADF photographers gave me," he said.

"[In] 2014, I toured that show to maybe 60 regional theatres around Australia, everywhere from the Tennant Creek RSL to the Princess Theatre in Launceston. It was rewarding, and universally I found people were curious."

Military links are stronger in country towns, where the army recruits a disproportionate number of young people. Every audience, it seemed, included those with close relatives in the armed forces.

"There's a connection there, and people wanted to understand the whole Uruzgan mission but felt that they didn't or felt that it hadn't been explained in a way they could understand," he said.

"They came out saying they'd learned more about that from that two-hour show than they'd learned from 15 years of media. And that was kind of what I was out to do, and it felt like an important thing to do because there was a whole generation of Vietnam vets who came back and didn't have their experiences explained and kind of walked the land as strangers for a long time."

"Now, we're a long way from that, there's no stigma around it, but I still think that it's not a matter of pitying soldiers, it's not about lionising them, it's just about actually understanding and comprehending the nature of their experience."

Still, it wasn't until late last year that he finally sat down and began writing, spending eight months, as he puts it, "arse on chair" working through his own experiences and getting them down in book form.

His driving motivation, in everything he does, has always been telling stories, and from his time in Uruzgan, there were plenty.

"It was interesting - too interesting sometimes," he says.

There were the long, hot months where he became intimately acquainted with the intricate details of rural Afghanistanis' lives, where he had to help deal with neighbourhood disputes, broken sewage systems, gastro outbreaks. He recalls speaking to a farmer whose young son was stricken with dysentery, guiding him up to the aid post, and watching the same farmer wheel his son's body out in wheelbarrow later that day.

It was also, on occasion, dangerous, although most of the time he was stationed on a large base, surrounded by armed soldiers. But there were incidents. One night, the cluster of shipping containers he was living in was hit by a rocket.

"It's a very alarming thing when you realise, in a concrete way..., someone over that hill who fired that rocket really wanted to kill you. It does get the adrenaline going," he says.

And, as is the case in all war zones, emerging unscathed was down to sheer luck. He recalls the frequent thought, walking with some soldiers past a donkey in the street, that if one of its saddlebags contained an explosive device, he was a goner. There never was such a device, for Smith. But the man who succeeded him in the job, Canberran Dave Savage, wasn't so lucky; same road, same soldiers, but this time, a 12-year-old boy in a suicide vest.

"Luckily the guy stumbled so Dave didn't take the blast in his torso, but he copped 60 ballbearings in the back of his legs, and he's had 18 operations since," says Smith.

It's not surprising, then, that the book was hard to write, although the narrative was clear. His initial posting, in 2009, had been for 18 months, after which time he was expected to come home and move on.

"The DFAT thing to do is to move on and do something different and new and cool, and a lot of my colleagues went to nice postings in Washington, for example. But I kind of stayed on the Uruzgan horse," he says.

He finished the album in 2011, and toured it, essentially reliving his experiences over the course of each show. The reviews were positive, and it was clear his words were affecting people. "I saw I had a role in explaining it to the Australian public, in a way that no one else was in a position to do," he says.

When the opportunity came up to go back for the last six months of the mission, against all advice, he put up his hand.

"It's one of the rules of DFAT - don't go back to a place, it will never be the same - but I decided to go just to see how the story would end, and to be in a position to tell that story," he says.

"The architecture for the book is the songs, but also it's similar to the show I did. I knew what story I wanted to tell, and it just took a while for that to crystallise.

"It was an emotional experience, and there were weeks when I was in a bad mood and difficult to live with."

He also kept working part-time, as he always has, and playing shows – the sweet balance he's found between his two personas. As the son of a diplomat and with a knack for the guitar, it's a duality he grappled with for some time.

"Personally, I was wrestling with it - should I focus on the music and make a go of that? Should I focus on a DFAT career and get more serious about it? Every time I reached a fork in the road, I just sort of kept going and ploughed onto the nature strip," he says, chuckling.

But since his first posting to Bougainville as a civilian peace monitor in 1999, he has known he has a particular talent for asking questions and building bridges between different worlds, whether through songs or straight-out diplomacy.

And he has, after a 20-year career, mastered the art of returning home, although the stark contrasts between our world and the other, between war and peace, aren't always easy to accept.

"The transition is always difficult - you grieve what you've lived," he says.

"When you're over there you get into it in a big way. It's fascinating, you feel purposeful, you're stimulated, and stretched and all those things. And it's a rich experience, if a little overwhelming. And then you get back here, and… it's Canberra."

But here, where he grew up and had most of his formative musical experiences, the air is clear and two-year-old Olympia is curled up on his lap. He has long stopped feeling any guilt over the injustice of the world.

"In Canberra, everything works! You don't see kids die, there's no conspicuous corruption," he says.

"It's our job to enjoy what we've got here. The greatness of what we've got here is highlighted by the dysfunction of a place like Uruzgan. I think I've finally got to a point where I'm happy to be home, comfortable, and living the good life."

The Dust of Uruzgan, by Fred Smith, is published by Allen & Unwin.

Fred Smith will be speaking about the book at Muse in Kingston on September 3 at 3.00pm, and will perform at Smiths Alternative on September 23 and 24.