In the late Sixties and early Seventies, when rock'n'roll seemed to find a new superstar every week, a gas fitter from Sheffield, England, enjoyed huge popularity, hit records and the respect of his peers.

His name was Joe Cocker, and nobody who saw Woodstock (the event or the film) could forget Cocker's spasmodic electricity. Later, he was responsible for some of rock's finer moments: "Delta Lady," "Hitchcok Railway," "Feelin' Alright" and the Mad Dogs and Englishmen tour featuring little-knowns like Leon Russell and Rita Coolidge.

Then it all fell apart. Always a little out of control, Cocker sank into an abyss. Bouts of depression led to booze and drugs that destroyed his body and voice, and he continually canceled concert tours and recording sessions. There was an occasional album, but nothing approaching the quality of his early work, and Cocker was given up for dead. His record company (A&M), generally known for its perseverance and sympathy, finally gave up on Cocker and it looked like he was destined to be another pop music nova - flash brilliance and then black hole.

Well, don't look now, but Joe Cocker is back again and - as Southside Johnny would say - this time it's for real. At least it sounds like it's for real.

Cocker's new album, "Luxury You Can Afford," is a jaunty compilation of rock and blues, and you can hear some of it live at the Warner Theater on Sunday. Normally, you might take a believe-it-when-I-see-it approach to a scheduled Cocker concert, but if "Luxury You Can Afford" is any indication, the performer has every reason to show up.

If you have never seen Joe Cocker live, prepare for an experience. Usually, you spend half the show wondering when Cocker will require hospitalization and the other half watching him get propped up straight enough to stand. In fact, Saturday Night's John Belushi (maybe now it's "Animal House's" John Belushi) owes much of his own stardom to Cocker's unorthodox stage antics.

Belushi began imitating Cocker early in his comedy career, parlayed it into a hilarious bit in the National Lampoon's original "Lemmings" show, and capped his Cocker parody by appearing with the man himself on an episode of Saturday Night.

Belushi's thrashings and collapses were very close to the real thing and, at the time, his voice was in better shape than Cocker's. No more.

Cocker still isn't Perry Como, but his voice on "Luxury You Can Afford" has a life in it that was missing from his past few efforts. His is a great while blues voice, and its raw edges and obvious pain added new dimensions to earlier tunes like "You Are So Beatiful (To Me)" and "I Could Stand a Little Rain." Then, though, he had no strength when he tried to rock, and his records from that period were decimated by an inability to get himself together.

On his new album, "Lady Put the Light Out" has the same feel as his other tear-jerkers, but Cocker and producer Allen Toussaint inject some energy into the mix, Harvey Thompson's sax solo accentuates the positive and Cocker pushes the tune to its full capacity.

Cocker's interpretation of "Southern Lady" shows that he still listens to a lot of Ray Charles records (Charles has called Cocker "my only real disciple") and Procol Harum's "Whiter Shade of Pale" becomes a near-hymn.

But it's the up-tempo songs that reveal Cocker's new lease on recording life. He starts off the album with Toussaint's "Fun Time," and immediately we hear him sing: "I've got a new resolution/Traded in my Mojo on a disco band/Got my mind set on a good time/You can come along, whatever shape you're in."

Joe Cocker? Good time? Is this the same person we watched disintegrate to the point that the Illustrated Encyclopedia of Rock, published in America in 1977 (England in 1976), stated: "Cocker is now virtually a recluse . . . and has often seemed one of rock's saddest casualties"?

Sunday night, the Warner Theater gets another edition of Joe Cocker.This one sounds inspired by his sidemen and delighted with his material. "Luxury You Can Afford" features most of Stuff. Donny Hathaway, Rick Danko, David "Fathead Newman, Hank Crawford and Dr. John Top players are no strangers to Cocker, who previously played with Steve Winwood, Albert Lee and Kummy Page - but these guys are more his style.

Besides "Fun Time," Cocker has a ball with "I can't Say No," "I know (You Don't Want Me Anymore)" and Bob Dylan' "Watching the River Flow." Ironically "Wasted Years" - which could have been his best vehicle for self-expression - bog down. And "Heard It Through the Grape vine," seemingly perfect for Cocker's heart felt wails, is rousing but overproduced.

Yet, "Luxury You Can Afford" is a luxury you can afford. Don't be put off by Cocker's reputation or past flops. The man can still belt out a song as well as any rock singer. Now that Rod Stewart has found a gold mine doing ballads, Cocker may be British rasp's only surviving practitioner. And the fact that Joe Cocker is surviving at all in reason enough to give his new work some attention.