But had Wallechinsky maintained the labour of love he has undertaken ever since 1984, when the summer Games were held with huge commercial success in Los Angeles, close to his home town of Santa Monica, he would certainly have revisited the 1976 men’s decathlon event from Montreal as part of his quadrennial task of addition, revision and amplification.

After describing the Olympic victory and third successive world record by Bruce Jenner of the United States in the most recent edition, Wallechinsky shifted his attention to the kind of value-added details that have made his magnum opus irresistible.

He added background and anecdotes to his account of the champion’s performance, concluding with a resume of Jenner’s married life – first with the woman who had been such a support during the long years of Olympic training, Chrystie Crownover, then with Linda Thompson, the “former girlfriend of Elvis Presley”, before the settling into “a third, more successful marriage.”   

The phantom 2016 version of this account would be considerably more bulky as it relayed the subsequent high profile progression in Jenner’s life, with that third marriage – to Kris Kardashian – eventually ending in 2015, by which time both partners had been involved in the massively popular reality TV show Keeping Up With The Kardashians for eight years.

It would also take in the startling public announcement made by Jenner in April 2015 that she was “for all intents and purposes” a woman, renaming herself three months later as Caitlyn Marie Jenner and confirming both the name and gender change the following year.

Wallechinsky’s Olympic book may be in abeyance, but Jenner is moving full steam ahead in publicising her forthcoming memoir The Secrets of My Life – due out on April 25 – in which, according to numerous reports in the United States including USA Today, she confirms that she underwent full sex-change surgery in January of this year.

“I am telling you because I believe in candour,” she is reported as saying in her memoir. “So all of you can stop staring. You want to know, so now you know. Which is why this is the first time, and the last time, I will ever speak of it.

“The surgery was a success, and I feel not only wonderful but liberated.

“I just want to have all the right parts. I am also tired of tucking the damn thing in all the time.”

Since the 26-year-old Jenner exited the Olympic Stadium in 1976 as victor ludorum, leaving behind vaulting poles that would never be required again, an athletics career par excellence has been transformed into a celebrity career.

Such was Jenner’s fame at the point when she announced her gender transition – in an interview with Diane Sawyer on ABC’s 20/20 programme – that it drew a TV audience of 20.7 million.

Jenner, who wrote her book with Pulitzer Prize-winning journalist Buzz Bissinger, is scheduled to promote the memoir with another interview with Sawyer on 20/20 on Friday (April 21).

Jenner has been described as the world’s most famous transgender woman, and the astonishing range and diversity of her life experiences has established her as a figure constantly making the news.

Amidst the noise and chatter of a celebrity-obsessed, digital age the quality of Jenner’s landmark sporting success tends to be forgotten. It ought not to be.

The Montreal Games decathlon brought Jenner into contention with two mighty rivals – West Germany’s Guido Kratschmer, and the Soviet athlete who had set personal bests in eight of his 10 events at the 1972 Munich Olympics to earn the gold medal and world record, Mykola Avilov.

Jenner, who had been 10^th in Munich, had trained relentlessly for the 1976 gold, supported by wife Chrystie, who worked as an air hostess. Jenner contributed to the family fortunes by selling insurance in the evenings – with days devoted to athletics.

Avilov’s victory in Munich had had an immediate and dramatic effect on Jenner, who recalled: "For the first time, I knew what I wanted out of life and that was it, and this guy has it. I literally started training that night at midnight, running through the streets of Munich, Germany, training for the Games. I trained that day on through the 1976 Games, six to eight hours a day, every day, 365 days a year."

Wallechinsky recounts: “At night, he dreamed about the different events so often that Chrystie could tell which one he was unconsciously practising.”

Strongest in the second day of events, Jenner had sought to be no more than 200 points down on the West German and Soviet competitors by the end of day one. As things turned out, the overnight gap was just 35 points from Kratschmer, and 17 from Avilov.

Gold was in reach –and finally confirmed with a bold finish in the following day’s concluding 1,500m, an event that was live on US TV.

After the event, Jenner started what has now become a traditional celebration for athletes, taking an American flag from a spectator and carrying round during the lap of honour.

"In 1972, I made the decision that I would go four years and totally dedicate myself to what I was doing, and then I would move on after it was over with. I went into that competition knowing that would be the last time I would ever do this," Jenner commented.

"It hurts every day when you practice hard. Plus, when this decathlon is over, I got the rest of my life to recuperate. Who cares how bad it hurts?”

With just two events remaining, Jenner had wept with emotion, victory all but certain. As Jenner rested on the infield, Soviet athlete Leonid Lytvynenko wandered up and insisted: “Bruce, you going to be Olympic champion.” “Thanks”, Jenner replied. Lytvynenko then asked: “Bruce, you going to be a millionaire?”

Jenner’s response was to laugh. But 40 years on, the millionaire status has been reached many times over – with the imminent book itself reported to have earned her an advance of $4 million (£3.2 million/€3.8 million).

The journey between that climactic day in Montreal and Jenner’s current high-profile, highly complex personal situation has been almost bewildering in terms of the territory it has covered.

Jenner became a national hero figure on returning to the States and, with agent George Wallach appointed, was soon dealing with a welter of commercial offers and opportunities.

Jenner was on the cover of Playgirl magazine and was spokesperson for Tropicana, Minolta and the Wheaties brand breakfast cereal.

There were relatively successful forays into motorsport – Jenner and co-driver Scott Pruett won their class in the 1986 12 hours of Sebring race in a Ford Mustang.

Jenner also launched several businesses in the early 80s, in the fields of exercise, aircraft supplies and software.

A mixed film and television career was building during this time. Jenner appeared in the disco-inspired comedy Can’t Stop The Music in 1980, being nominated for the Golden Raspberry Award for Worst Actor. The film scooped the Worst Picture Award.

The US TV career was more successful. In 1981 and 1982, Jenner appeared in six episodes of the highway police comedy series CHiPS as Officer Steve McLeish. Over the next 20 years, there were a succession of other appearances in game shows and reality TV programmes including The Apprentice, I’m A Celebrity..Get Me Out of Here, The Weakest Link and Skating with Celebrities.

But in late 2007, the TV profile rose exponentially with the start of a reality show that featured Jenner and her family. Keeping Up With The Kardashians (KUWTK) featured Jenner, then wife Kris, their daughters Kylie and Kendall Jenner, and the four stepchildren – Kourtney, Kim, Khloe and Rob - from Kris’s earlier marriage to Robert Kardashian, the attorney who helped in the successful defence of OJ Simpson during his controversial 1995 murder trial, and who died in 2003.

The show has been criticised in many quarters as being an empty vessel filled with characters famous only for being famous, but alarmingly adept at self publicity. But it has also proved enduringly popular, with the most recent editions on the E! cable network drawing more than three million viewers.

For Jenner, 2015 proved to be a uniquely challenging, and difficult year. In February of that year, she was involved in a fatal multiple-vehicle collision in Malibu, California, during which Kim Howe, an animal rights activist and actress was killed when Jenner’s SUV collided with her car. No criminal charges were brought concerning a confusing sequence of events, but three civil lawsuits – one still ongoing - were brought by Howe’s stepchildren and drivers of other cars in the collision.

Two months later, Jenner made her public statement, telling Sawyer that she had dealt with gender dysphoria since her youth, and adding that she had cross-dressed and taken hormone therapy after her second marriage had broken up, but halted those courses of action once she had met Kris Kardashian.

She followed up in a Vanity Fair interview with Bissinger, and was photographed by Annie Leibovitz for a front cover which carried the headline Call Me Caitlyn.

Using her Twitter handle @Caitlyn_Jenner, she tweeted: "I'm so happy after such a long struggle to be living my true self. Welcome to the world Caitlyn. Can't wait for you to get to know her/me."

Jenner amassed over one million Twitter followers in four hours and three minutes, setting a new Guinness World Record and surpassing United States President Barack Obama, who had required four hours and 52 minutes to achieve the same total a month earlier. Four days later, Jenner was up to 2.37 million followers, with another 1.5 million followers on Instagram.

However, Jenner also received criticism. Beginning in September 2015, she was depicted on the satirical American animated programme South Park, which parodied her supporters' political correctness as well as her driving record.

In July 2015, the E! network began a series of eight one-hour documentaries focussing on Jenner’s life post gender transition, entitled I Am Cait. The critical reaction was far more favourable than that which had greeted KUWTK, noting the show’s more serious tone, but I Am Cait was cancelled in August 2016 after two series due to low ratings.

In one episode early last year, Jenner – a self-proclaimed Christian and Republican - said that although she did not support Donald Trump, she thought he would be good for women’s issues. She added that she would never support Hillary Clinton.

In February 2017, President Trump rescinded federal requirements giving transgender students the right to choose the school restroom matching their gender identity. In response, Jenner tweeted: "Well @realDonaldTrump, from one Republican to another, this is a disaster. You made a promise to protect the LGBTQ community. Call me."

Jenner’s tumultuous year of 2015 also included having to defend her position against a slyly-worded and ugly petition containing more than 10,000 names was sent to the International Olympic Committee seeking to have her Olympic title revoked in the wake of her transgender announcement.

The petition's mission statement read: "It has recently come to light that gold medalist Bruce Jenner is in fact transgender, and therefore, identifies as a woman. We congratulate Ms Jenner on these new developments and wish her the best.

"However, this creates somewhat of a problem as Ms Jenner (as talented as she is) claims that she has always believed herself to be truly female, and therefore, was in violation of committee rules regarding women competing in men's sports and vice versa.

"It is only fair to all involved that women receive their credit as champions of the Decathalon [sic] and that the men racing Ms. Jenner are not expected to compete with a superior, streamlined being such as herself.

"We urge Ms Jenner to support the transgender community by giving up the medals earned by competing against the wrong gender."

In its response to the petition, IOC Communications Director Mark Adams announced, succinctly and conclusively: "Bruce Jenner won his gold medal in the 1976 Olympic Games and there is no issue for the IOC."

Jenner’s Olympic status will stand for all time; Jenner’s public ratings are another thing entirely, although perhaps the revelations in her new book will see her profile rise once again.