Leonard's love-hate relationship with the sport is well known. A professional career following a gold medal at the Montreal Olympics of 1976 has seen Leonard fight just 39 times (including two losses and one draw) in 20 years, statistics put into perspective by those of 80s contemporaries Thomas Hearns (62 fights), Marvin Hagler (67 fights) and Roberto Duran (112 fights).
Of the quartet whose memorable rivalry sustained the sport throughout a depressing mid-80s slump, only Hagler has walked into the sunset never to look back. Hearns and Duran have kept plugging away, diminishing their reputations by the fight.
Leonard, though, has retired six times to date, always to return: the first retirement following his Olympic success; the latest after Terry Norris brutally battered him for 12 rounds in February 1991, prompting one American journalist to describe the beaten Leonard as "staggering from the Madison Square Garden ring like a mugging victim".
A detached retina, a period of cocaine abuse, the lack of challenge, all have caused Leonard to retire in the past, yet always he has found justification to return. But why now, at an age where he feels it prudent to undergo yearly prostate examinations, does Leonard feel driven to risk his health and reputation once more?
Not through financial necessity. Leonard hardly needs the $5m (pounds 3.2m) he receives for challenging Camacho, who earns $2m. Leonard and his attorney, Mike Trainer, have maintained total financial independence from day one. The investors who paid $1,000 apiece to get Leonard's career up and running were repaid from the proceeds of his first professional fight and summarily dismissed. Leonard and Trainer went their own way, forgoing promotional alignments and fighting for the highest bidder, earning over $100m to date.
Neither is this comeback through lack of achievement. He was inducted into the Boxing Hall of Fame five years ago. Leonard has won six world titles in five weight divisions, a record beaten only by Hearns.
It is the search for approval, for adulation, that brings Leonard back and boxing has, since his teenage years, provided both. As a frail, timid youth in Palmer Park, Maryland, whose only sporting aspiration was to be a gymnast, Leonard was something of an embarrassment to his father, Cicero. But when the youngest of the Leonard brothers took up boxing and showed promise, the dysfunction disappeared from the father-son relationship.
Boredom also plays a part. A career in television commentary, a spell as "boxing ambassador" for a Las Vegas hotel-casino - Leonard's sole duty being to play a few rounds of golf with the establishment's high-roller customers - and the launching of a foundation for underprivileged children, none replaced the adrenalin rush of the boxing ring.
"Fighters are a rare breed. We don't ever think we slow down," Leonard said. "I guarantee if you polled 12 fighters and asked if they could beat Roy Jones Jnr, they'd say yes. Because, if you don't believe you can, you already lost. And, yes, I believe I could knock out Roy Jones Jnr, too.
"When I hit my 40th birthday, I realised it was now or never. I've done a lot of self-evaluating and, with each day, each year, I realised my chances of restarting my career were getting slimmer and slimmer."
On perhaps damaging his reputation by taking one fight too many, a philosophical Leonard said: "If one fight tarnishes my career, then my career was never worth much anyway."
For all Leonard's triumphs - stopping the frighteningly powerful Hearns in their first fight, forcing the animalistic Duran to quit in their second, bedazzling iron man Hagler and sending him into retirement - recent memories are of the faded fighter of Leonard's last two contests: the one who sustained 60 stitches to facial wounds in the third fight with Duran; and the man who through grim resistance alone lasted the distance against Norris after twice being floored. Leonard's refusal to spar in public has done nothing to dispel those images.
Camacho, 34, is a multi-weight champion himself, but lack of self-discipline has dogged the career of the Puerto Rican-born native of Spanish Harlem in New York.
The former Rikers Island inmate has a history of drugs and firearms offences but is a highly skilled fighter with fast hands, good mobility and a reputation for durability, never having been stopped in 66 fights, including three losses and one draw. And, most importantly, Camacho has fought 27 times during Leonard's most recent spell of inactivity, a factor that makes this an even-money fight with Las Vegas oddsmakers.
"It's all on me, I know that," Leonard said. "It's basically what I do, what I have left - 50 per cent beats Camacho, 75 per cent beats him comfortably, and 100 per cent ... annihilation."
The crowd at the Atlantic City Convention Centre waits to watch Leonard play the percentage game.
The Sugar Ray story
July 1976 Wins light-welterweight gold medal at Montreal Olympics.
February 1977 Turns professional.
November 1979 Wins first world title against Wilfredo Benitez.
June 1980 Loses for first time to Roberto Duran.
November 1980 Gains revenge over Duran.
September 1981 Stops Hearns for undisputed world welterweight title.
February 1982 Retires because of detached retina.
May 1984 Returns with win over Kevin Howard then retires a second time.
November 1988 Beats Donny Lalonde to win super-middleweight and light- heavyweight titles in one fight.
April 1987 Ends three-year retirement to beat Marvin Hagler for WBC middleweight title.
June 1989 Floored twice in controversial draw against Hearns.
December 1989 Beats Duran in third fight of their series.
February 1991 Floored twice and beaten by Terry Norris and announces retirement.
1 March 1997 Aged 40, returns to fight Hector Camacho.Reuse content