Living on borrowed time didn't stop Bobby Darin from being sure he'd be a legend by the age of 25. He was the singer who wanted to steal Sinatra's crown, the actor who dreamed of silver screen success - and of course, the guy who wrote a song about a sharp-edged hamburger...

Mc Donald's is not just a hunk of cooked flesh. The company fought its way to the top by nous, know-how and sheer chutzpah. Recently, like Levi's, they tumbled to the fact that the use of a zillion-selling record could enhance their sales. So they created a TV commercial based on Bobby Darin's version of "Mack the Knife," linking the Big Mac's name to that of a pop legend - which Walden Robert Cassotto unquestionably was.

Grabbing the name Darin from a faulty Chinese eatery sign that should have read (Man)darin, he blitzed his way to the forefront of the '50s rock'n'roll teen scene, then wooed the Copacabana crowd and set his sights on taking Sinatra's crown. And when he wasn't singing or playing keyboards, vibes, guitar, bass and drums (we're not dealing with your usual vocal cowboy here) he moved into acting, winning an Oscar nomination and the French Film Critics' Award for his role in Universal's Captain Newman, MD.

He had a perpetual problem, though: the fact was that Darin, Bronx-brash and arrogant, was living on borrowed time. A victim of rheumatic fever three times as a child, he possessed a heart that was liable to cease ticking at any time. For years he was forced to carry an oxygen tank and mask around as part of his tour equipment, because without them, he could have died at any minute.

Musically, his start came via the self-penned "Splish Splash," a 1958 novelty rock hit about a guy who was taking a bath, found a party going on and then decided to join in the fun.

Though Darin's Atco single crossed the Atlantic to wedge itself in the UK charts, it found itself barred from the highest rankings by a cover version shaped by comedian Charlie Drake, purveyor of pop-pourri like "Puckwudgie" and "My Boomerang Won't Come Back." "Splish Splash" was that sort of song. It was hardly an auspicious start for a performer whose one desire was to be listed among the all-time greats. "You'll vomit when you hear it." Darin told a friend. But he'd got one foot in the door. And now he could start kicking.

"Queen of the Hop," his next hit, kept things ticking with the Prom crowd. A better move was "Dream Lover," another Darin composition, which held his teen fans but also proffered hope that his wares weren't all made of candy floss. "I have rock'n'roll hits. But I have to go beyond rock'n'roll. I have to prove I can sing." Darin proclaimed.

He had always maintained that he would be a legend by 25, so less than three years were left in which to make it. Accordingly, he linked up with an outstanding arranger, Richard Wess, who helped Darin shape a Sinatra-style album titled "That's All." From the album were culled hip-hip-hip renditions of oldies such as "Beyond the Sea," a French MOR favorite which stemmed from 1938, and "Mack the Knife," a song that started life in a Berlin production of Kurt Weill and Berthoid Brecht's "Threepenny Opera" in 1928. Released as singles, these tracks became chart-busters, and when "Mack" hit the top of the US charts it held on for nine weeks.

Though generally regarded as a braggart, Darin rapidly moved into Sinatra territory. He became a crowd-puller on the Vegas circuit ,and a 1960 show at the New York Copa proved to be one of the events of the year. Darin performed a soft-shoe routine, playing down-home piano and jazz-tinged vibes, exchanging one-offs with stage-side personalities like Joe Ross (Bilko's Dobermann) and singing in a manner that Dorothy Kilgallen observed "had all the nerve of a bank robber." New York Mirror columnist Walter Winchell even wrote a sonnet in his praise, and the New York World averred with his stated goal -- as reported in Life --by saying, "Darin may still be the biggest thing in show business by the age of 25 -- if he doesn't burn himself out!"

Darin signed his first film contract in 1959, but in truth he was waiting for the right vehicle to provide his acting debut. "I don't think I'm mature enough yet to see what one role it is," he claimed, "but I do know I don't want to be billed as 'Bobby Darin in Rock Around the Rumble Hall'," In late summer 1960 he became fourth lead in Come September, cast as a college boy visiting Italy who falls for another American tourist, played by Sandra Dee, America's uncrowned teen queen since her appearance in Gidget, the first surf movie for the jukebox generation. By December of that year Ms. Dee had become Mrs. Cassotto.

But Darin sought roles of more substance in Hollywood. He became accepted as a creative actor following a part as idealistic trumpeter Ghost Wakefield in Cassavetes' Too Late Blues. Gradually he began to build his film career, announcing in typically unrestrained manner: "Some day I want to have an Academy Award." He nearly gained the plaudit when a part in Stanley Kramer's Pressure Point came his way. Playing a soft-faced, psychotic Nazi who hated Jews, Darin was a revelation. Kramer stated: "I think Bobby touched upon genius." But the film, though critically acclaimed, flopped at the box-office, and when Oscar time came around Hollywood just didn't want to know.

Though he'd sold over a million copies of "Mack the Knife," becoming one of America's highest paid entertainers at the same time, by his own standards Darin was something of a failure. "Two and a Half Months To Go" screamed the banner headline in Newsweek, 1962, as Darin neared his 25th birthday. He didn't need reminding.

The hit records were still coming, as a version of "What'd I Say," recorded with The Blossoms (forbears of The Raylettes with Ray Charles) went Top 30, and the jaunty, hicksville "Things" clambered up to Number Three in the US singles listings. But problems mounted. During one Copa stint, Darin lost his voice, and had to be replaced by Sam Cooke. And a tour with the Count Basie band proved a no-no, when only 2,000 punters turned up for one Boston concert in a hall that seated nearly four times that number.

Frustrated, Darin ditched Atco and signed a record deal with Capitol, which turned out to be a less-than satisfactory move. Even his hair began thinning, and he was forced to suffer the ignominy of wearing a toupee. The only really good news concerned the arrival of his son, an event which, temporarily, put an end to scurrilous media stories.

Cast as a troubled, ill-fated corporal in Captain Newman MD, Darin acted his (failing) heart out. Nominated for a 1963 Academy Award, he felt that he could fulfill yet another of his announced ambitions, though it was Melvyn Douglas who finally received the prestigious plaudit, for his part in Hud.

Following another bout of ill-health, Darin retired from live performances and, for a while, concentrated on writing and publishing. It was during this period that he became a civil rights activist, taking part in marches on Washington. In 1965 he joined Harry Belafonte, Dick Gregory and Peter, Paul And Mary in entertaining a mass march in Montgomery, Alabama.

Once told by a doctor that he would never live to see his 30th birthday, Darin celebrated this threshold on May 14, 1966 with some relief, though he knew each passing year was a bonus. The press hadn't forgotten his earlier boasts, and The New York Post commemorated the event with the headline: "Egotist Bobby Darin Hits Low Note As Legend." That year, back with Atlantic (parent company of Atco) he notched his final massive hit with a cover of Tim Hardin's "If I Were a Carpenter." He went back on the road again. And, he also divorced Sandra Dee.

A political future now loomed. He began campaigning for Robert Kennedy and, in 1968, decided to run for public office. It was then that Nina, the woman he had known all his life as his sister, threw his ambitions into turmoil when she announced that she was really his mother! Unmarried, she passed Bobby off as her brother after bringing him home from the hospital.

This situation continued throughout the years, and doubtless would have gone on forever but for Darin's political opponent discovered the truth and revealed it in humiliating circumstances. The truth about his birth shattered all illusions about achieving any high post within the Democratic party, but Darin's support for Robert Kennedy continued unabated.

The singer's friend and manager Steve Blauner later reminisced: "Bobby would be on the the plane with the Senator and they'd sing together. When the assassination happened, Bobby freaked out. He went to the grave-side to wait for the body. He told me that he had a vision at the grave-side -- some weird religious experience that made him stop working."

Soon after Kennedy's death, Darin sold his possessions and moved to Big Sur, on the Californian coast, where he lived in a trailer for the next year. Then, in 1969, he returned to active life in LA where he formed his own record company, Direction. No longer the tux-touting entertainer of the Copa era, he appeared in blue jeans, working with a rock band. He wrote protest songs and put out two albums that dealt with tough subjects like the Kennedy assassination, Vietnam and the discovery of bodies at an Arkansas prison farm. He paid the penalty for his sustained hard work.

After a four-week Vegas engagement in early 1971, he was forced to have two heart valves replaced in a nine-hour operation. After pulling through, he celebrated by marrying a beauty named Andrea Yeager. Around the same time, he signed to Motown and recorded an album. But, on stage and at home, he was becoming increasingly difficult to live with. He was emotionally and physically a wreck. The marriage lasted from June until November, and at the same time his heart was giving signals that it, too, could last little longer.

On December 19, 1973, the 37 year-old Darin entered LA's Cedars of Lebanon Hospital for his second bout of open-heart surgery in two years. This time, the surgeons fought for eight hours without result. On December 20, he was pronounced dead. Aged 37, he had directed that there were to be no services and that his body was to be donated to UCLA's medical school. Grammy winner for best new Artist at 23, Darin claimed at the time: "No, I don't want to be Sinatra -- I want to be the biggest Bobby Darin I can be, the best Bobby Darin in the world." And that goal, at least, he achieved.