When Bobby Darin died after heart surgery — on Dec. 20, 1973, at age 37 — Time magazine resurrected a comment the singer had made 14 years earlier. His goal, Darin had told Life, was ”to establish myself as a legend by the time I’m 25.” Though Time concluded he hadn’t achieved that ambition, time has proved otherwise: Darin was most definitely a legend, as well as one of his generation’s most electrifying entertainers.

In his 20-year career, Darin (born Walden Robert Cassotto on May 14, 1936, in the Bronx) was a teenybopper idol, a romantic crooner, a jazz hepcat, an R&B shouter, a movie star, a TV personality (on his own variety shows and as a guest on others), a songwriter, a Democratic party activist, a folkie, a record label impresario, and a Las Vegas lounge lizard. ”All that drive was because he realized he wasn’t going to have a full life,” said son Dodd Darin, 36, referring to a life-threatening attack of rheumatic fever his father suffered at age 8, which led doctors to predict his death within a decade. ”You better believe he was a man with a mission.”

As a teenager, Darin taught himself guitar and piano; he even cowrote his rock & roll breakthrough, 1958’s ”Splish Splash,” which reached No. 3 on the charts. A year later, Darin cut his first album of standards, That’s All, which earned him two Grammys and yielded ”Mack the Knife,” one of the biggest-selling singles of all time. From there he hopped to Hollywood, acting in films like 1961’s Come September (costarring a teenage Sandra Dee, his wife from 1960 to 1967 and mother of restaurateur Dodd; in 1973, Darin married — and divorced — legal secretary Andrea Joy Yeager). His movie career climaxed with an Oscar-nominated turn in 1963’s Captain Newman, M.D.

Darin patterned himself after Elvis, Sinatra, Dylan, and Ray Charles, but his own finger-snapping, tie-loosening, swinging-lover personality resonated through all his stylistic guises. Proof of his enduring appeal: two extensive boxed sets; a pair of recent biographies, including one by Dodd; and a screenplay based on Al DiOrio’s 1986 bio Borrowed Time (director Barry Levinson is interested). ”Bobby didn’t have Nat King Cole’s voice or James Dean’s looks,” said Nik Venet, one of Darin’s producers, ”but he’d step on stage and become everything you ever thought was a star.”