These days, Smith looks fit as a fiddle. His once jet-black hair has turned grey and his famous big, thick glasses are now pared-back thin steel rims.

But he is still, essentially, as lean and upright as when he first entered the public sphere more than 50 years ago as the savvy salesman who wasn't afraid to make fun of himself to make a quid.

Smith is sitting in the warm country kitchen of his Gundaroo property, his bolthole for 26 years, bought because it was close enough to Canberra for meetings, especially when he was the crusading chair of the Civil Aviation Safety Authority and far enough away from the "bureaucratic cocoon" of the national capital. He and wife Pip recently changed the property's name from Bowylie Station to Talagandra Station; he was sick of people mispronouncing the former and the latter was found to be the original name of the area in any case. Smith has no plans to sell the property, which has a full-time on-site farm manager.

"We'd like to keep it in the family for a long time," he said.

The grounds of the property are stunning but understated, all lush lawns, ornamental ponds and comforting cottage-garden plantings. Although there is still the indulgence of the air strip so Smith can fly in and fly out. And the 2km train track down which he can send his own 1904 steam engine.

Smith was making one of his first visits back to Gundaroo since Sydney came out of COVID-enforced lockdown. Pip was at home in Terrey Hills. The couple have been married for 52 years and My Adventurous Life is as much about her support for her husband's business and thirst for adventure. But, as in life, Pip still remains happily in the background of the book, while Dick is firmly centre stage.

"Everyone kept saying to me, 'Why haven't you done an autobiography?' and I would say, 'Well, I'm too busy and my life isn't over yet'," he said, sitting at the kitchen table.

"It was really Richard Walsh, the managing editor of Allen and Unwin who convinced me to do it. The only reason it happened was lockdown last year. I didn't have a lot to do so sat down and started writing the book."

The book is dedicated to Smith's grandchildren and on first glance it seems like it is a message to all kids - and their parents - to stop being so risk-averse and to get out and have an adventure. It is a paean to the free-range childhoods of post-war Australia, although young Dick probably took it to the nth degree, from the age of four happily wandering alone into the bush around his childhood home in the northern suburbs of Sydney and even exploring the stormwater drains that emptied into Middle Harbour.

His parents were loving - his mum did get the council to put bars on the drains - but they allowed him the freedom to roam, which Smith acknowledges is almost impossible to replicate now.

"I think I won the lottery of life. I was born in Australia in the 1940s, and there weren't any rules," he says.

The book is also the story of the boy who hated school and who thought he was dumb, but eventually went on to create a business that would one day turn over $1 billion a year.

"It's got a message to all kids that you can be hopeless at school, but don't write yourself off, you can still do OK," he says.

"I had a terribly inferiority complex. Now, you'd probably call me dyslexic. But in those days, they just thought you were dumb. So I left school at 15, thinking I was completely hopeless. And even now, I don't have any qualifications. And even though I recommend to people, 'Get as many qualifications that you can', even if you can't, you can still do OK, especially in Australia."

More than OK. He says he got that early push to take a risk and believe in himself from being part of the Scouting movement, from a girlfriend who told him he wasn't dumb and from a family friend who urged him to stick to his passion for radio rather than become a park ranger.

The first Dick Smith Electronics store opened in 1968 in an underground carpark of a suburban shopping centre in Neutral Bay, selling and servicing car radio equipment. Smith was 24 and had invested $610 of his own money in the shop - $600 from the sale of a second-hand boat and $10 from the savings of his soon-to-be wife Pip. (Smith also had the backing of a $12,000 low-interest loan from a wealthy friend and fellow Scouts enthusiast Dr Tony Balthasar). When Smith sold Dick Smith Electronics, which had become wildly successful selling imported electronic components, to Woolworths in 1982, it was turning over $50 million a year and employing 500 people.

It's easy to forget that for almost 40 years Smith has had nothing to do with the electronics business that still bears his name. He was masterful at getting free publicity for the business from the media, his first stunt importing petrol-powered pogo sticks from the United States which he planned to sell to the housewives of Australia to ride to the shops. He and his face were forever linked with the business.

The Dick Smith brand is now owned by Kogan.com, the all-pervading online company started by Belarus-born Australian Ruslan Kogan. Smith says he's never been concerned about selling the Dick Smith name.

"So far so well," Smith says, of Kogan's ownership.

"He hasn't damaged the name as far as I know. Woolworths were very good with Dick Smith Electronics, they ran it for 29 years. But their mistake was, as all public companies do, is that they had this pressure to grow forever. I told them when I sold the business that you could have about 100 Dick Smith shops. I think I had about 36 when I sold them.

"Well, Woolworths ended up opening 350 shops. The reason they sold it, it was still making good profit, is that they wanted more growth. So they sold the business [to Anchorage Equity]. They bought it for $115 million, they floated it for $520 million. And within two years, it was broke."

Kogan.com bought Dick Smith brand name in 2016 and the business is now entirely online. It's a far cry from the early days when Smith was all about putting bricks-and-mortar shops in high-profile locations, making savvy investments along the way. ("Most people believe that my money-making success has come from electronics and publishing, when actually most of it has come from the purchase and ownership of commercial properties," he writes in the book.)

Smith's sale of the electronics company to Woolworths gave him $25 million to pursue his adventures and bring to life projects that meant something to him, Geographic Australia, later sold to Fairfax, and Dick Smith Foods, which generated retail sales for Aussie farmers of almost $500 million, but eventually shut down because it couldn't compete against the likes of Costco and ALDI. (Smith saves special contempt for ALDI, describing the German grocery chain as "the most ruthless retailer in the world" which cut margins by "hardly employing anyone".)

A teetotaller, Smith found adventure was his drug of choice. Among his outlandish achievements were balloon flights across Australia and from New Zealand to Australia, a solo flight to the North Pole by helicopter when the cabin temperature fell to minus 38 degrees and around the world flights by helicopter and turbo-prop aircraft. Smith reckons they were managed risks, even though he cheated death more than once, mostly by flying into bad weather.

"I didn't start my adventuring until I was a multi-millionaire and that meant I could afford the safest equipment," he says.

"I'd say, 'What's the safest helicopter in the world?'. And they'd say, 'It's the Bell JetRanger but it's the most expensive'. But I could afford to buy one. I've done five risky flights around the world, two quite risky balloon flights, and the reason I'm alive is because of modern technology."

Yet the book does allow for some introspection. Smith's favourite family photograph is of him with Pip and their girls Jenny and Hayley in 1983 as he prepared to take off on the last stage of his solo helicopter flight around the world, taking him from Sydney to Fort Worth, Texas. He would fly across the Pacific Ocean, landing and refuelling on a tanker off Japan along the way. The "riskiest thing I have ever done in my life". It seemed insane but Smith achieved his goal. "I look back now and think I must have been mad to leave such a wonderful family," he writes, of that farewell photograph.

Smith says his adventuring days are over. Although he and Pip are still going to complete a leisurely 4WD trek around Australia, cut short by lockdown. "All of my heroes, people like Bert Hinkler, Kingsford-Smith, they all lost their lives because they kept pushing the adventure and one day the risk catches up with you," he says.

Smith's focus now is on philanthropy. He has donated more than $70 million to charity and intends to give more. At his book launch on November 10, he intends to give $5 million to 55 charities.

"Many social ones, St Vincent de Paul, The Salvation Army, the ones who help people who are hurting," he said.

And he wants others to as well. "I am very disappointed about the billionaire class in Australia," he says. "We have 100 billionaires and only 15 per cent of them are known as philanthropists. I think it's an obligation to give publicly. That's the ethos in America. If you're wealthy in America, you're also known as a philanthropist, it's automatic. Whereas in Australia, we've got a lot of wealthy people who are stingy."

And he will continue his campaign for population control, by limiting immigration to 70,000 a year; maintaining he is pro-immigration, but not to levels of 250,000 a year that put Australia's environmental and social wellbeing at risk.

"I explain very clearly in the book that I've been advantaged from the growth in Australia, but I'm still very vocal. I've spent millions of dollars in the advertising campaign saying we have to live in balance. It's amazing to me no major political party has a population policy," he says.

Smith's fear is that Australia's population could explode to 100 million.

"It won't affect me, but my grandchildren could still be alive at the end of this century when it could get to 100 million. And I'm a believer in human-induced climate change and so how can you increase your population by four times and do anything about climate change?"

In the end, that iconic business, Dick Smith Electronics, remains the thing he is most proud of, and something that has left a legacy.

"Not only did I employ lots of people, but I did quite well out of it myself," Smith says, for once making an understatement.