It's show time in a Dallas dinner theater and 600 buffet meals have been consumed and cleared. A four-piece rockabilly band is running out its last warm-up as the lights are dimmed. At $15 a head, the crowd has not been drawn by assembly-line sirloins but by a rock'n'roll musician of legendary dimensions, Jerry Lee Lewis, aka the Killer. The Killer is 43; half his life ago he was, with Elvis, at the vanguard of a cultural revolution. Radios blared his classics Whole Lot of Shakin' Goin' On and Great Balls of Fire. Then scandal overwhelmed him in 1958—marriage to his 13-year-old second cousin Myra Gail Brown. She was his third wife, and he was not yet divorced from his second. More than $100,000 in concert bookings were canceled. DJs, promoters and mothers boycotted Lewis' music. At 22, the Killer became rock's first superstar casualty.

In the last 10 years Lewis has built another career in Country & Western music, a genre far more suited to a man's fifth decade. But this night in Dallas, as always, Jerry Lee's past is the lure. They've come to see if he is still the volatile, crazed performer they remember, flailing the piano with forearms, wrists, thumbs, elbows, heels and even his rump.

Lewis emerges from a bright dressing room into the darkened hall. He stands unsteadily in a white jacket and ruffled shirt. A uniformed man with a gun and a flashlight points the way. Lewis is on intimate terms with the law, having been arrested for, among other things, drunkenness, waving a .32 at Elvis Presley's gateman and alleged possession of amphetamines. Earlier this month in Memphis Lewis was found guilty of driving while under the influence of drugs, and he will be sentenced in May. But this roomful of Dacron cowboys is on hand to celebrate, not condemn, his obstreperous spirit. The guard beams his flashlight at the floor. "I can't see the steps," Lewis says, clutching the man's arm and stepping into the spotlight.

Applause and whistles greet him. He sits at the piano, sips a beer and announces, "I drank too much whiskey before comin' out here tonight. It'll wear off." Before it does, he leans back and with stiffened, outstretched arms pummels the keyboard—those signature boogie-woogie phrases—fluttering his fingers in excited trills. "Tell ya mama / Tell ya pa / Get y'ass back t'Arkansas!" The band takes 12 bars. Lewis plays with his right hand, hits on the beer with his left. "See that girl with the red dress on / She can do it do it do it do it all night long." On the fast numbers, Lewis seems to sing in blissed-out rockabilly tongues. Then he slows for a C&W ballad—he can shift from raging boogie to red-neck melancholy like no other singer. "Girl I trusted in you / That was Jerry Lee's greatest sin / I love you still / You win again."

The voice is plaintive. It cuts like a laser of grief through the haze. He is enveloped by his own feelings; he seems to perform only for himself. The song ends. He takes off his coat. Sips beer. Whips out a red comb from a back pocket, rakes it through thick brown waves of hair. Texans yelp, women in the last rows sigh. He starts Release Me, stops short. "Awwww. Always hated that damned song. Elvis was destroyed by one woman. Five got to me. And that ain't includin' my cousins. Ain't nobody released me. Heee-heee."

It's a goofy, involuted monologue; his patter is like a running in-joke shared with no one but his God. "They tell me the grave's a mighty lonely place / That mutha-humpa with the shovel's throwin' dirt right in yo' face." Then it's his recent country hit, Middle Age Crazy, which has eerily appropriate lyrics—"And the young thing beside him / You know she understands / That he's middle age crazy / Tryin' to prove he still can." Lewis gets up, kicks back the stool, stiffens his legs, hunches over the keys and tears into his finale, his limbs like jackhammers. "You shake my nerves and you rattle my brain / Too much love drives a man insane / You broke my will but what a thrill / Goodness, grrr-ACIOUS, Great Balls of Fire." It's the moment the diners had hoped for, the confirmation that primordial rock'n'roll lives—in them, like Lewis, ageless and vital.

The show and the man are incandescent, unpredictable, lusty, defiantly vulgar. The Killer is sweating, his eyes bloodshot, his body depleted—the armed guard helps him back to his dressing room. "Thank God these good people still come to hear me play," Lewis says, reviving. In an hour, thank God, 600 more will be out there and he'll do it again.

Since Presley's death last summer, Lewis' career has surged, perhaps coincidentally. He was on the road for 11 months in '77, has had two LPs (his biggest sellers in years) on the C&W charts and will release two more shortly. He has made a number of TV appearances, some in conjunction with the current '50s-style R&R movie American Hot Wax. Another one, Grease, is due this summer. In Hot Wax he sings one song and was paid $35,000 for a week's work. Even before Elvis died ("I had a lotta things to say to him and never did," Jerry says sadly), Nashville writer Nick Tosches in his book Country: The Biggest Music in America called Lewis "the heart of redneck rock'n'roll and, maybe, the greatest country singer alive."

Lewis is surprisingly professional about his music. He arrives for recording sessions on time. Once in the studio, sipping Coke laced with whiskey, he can lay down tracks at a pace that is formidable even in the arch-efficient Nashville studio world. Says his producer Jerry Kennedy, "It's an infectious thing with Killer. The top session pickers respect him deeply as a musician and always get excited when he's in. Most times, he hears new material once, rehearses once, I turn on the red light and he hits it on the first take. Recently we cut 15 sides in four three-hour sessions." Says Lewis, "I'm in the swing again. If God lets me live the next 10 years, I'm hopeful things will be a little more pleasant."

He has a right to hope. Born to a poor rural family in Ferriday, La. (father Elmo was a carpenter and mother Mary Ethel preached in the Assembly of God Church), Lewis played the piano during services while growing up. As a teenager he was thrown out of a Bible school in Waxahachie, Texas for playing My God Is Real boogie-woogie style. His closest pals were cousins Mickey Gilley, now a C&W singer, and Jimmy Lee Swaggart, a big-time radio evangelist. Synthesizing gospel, hillbilly, Dixieland and black blues—all indigenous to the South—Lewis played clubs around Natchez, Miss, for three years before cutting his first hit, Crazy Arms, for Sam Phillips' Sun label. That was 1956 and the C&W record went to No. 1. Within a year Lewis had recorded his two famous rock tunes (they've sold 11 million copies) that made him Elvis' peer.

Jerry Lee on the piano seemed to pump chords straight into the adrenal glands of American youth, and his voice was raw, loaded with inflections of menace and sexuality. Then, at the start of a massive European tour, his six-month-old marriage to Myra was revealed. Accused of being a bigamist, he explained his bizarre marital history. "I was 14 when I first got married. My wife was too old for me; she was 17. Then I met Jane Mitcham. One day she told me she was going to have my child. Her brothers were hunting me with whips. I was real worried so I married her, but never properly. She divorced me, though she didn't need to. She was never my wife." Their child was called Jerry Lee Jr.

By Myra, Lewis had a son, Steve Allen (named for the comic who invited him to play Whole Lot of Shakin' on TV when it was banned as "vulgar" on radio), and a daughter, Phoebe Allen.

For several years after the scandal, Lewis appeared in honky-tonks (for $350 a night, down from $5,000) but could not manage a hit. The Motown and British sounds through the mid-'60s further blunted his (and Elvis') appeal. In 1962 it was personal tragedy that set him back. Three-year-old Steve drowned in a swimming pool.

In 1968 Lewis returned to C&W and topped the charts with Another Place, Another Time. A string of solid Nashville hits followed. Then in 1970 Myra left him after 13 years. "She was the only woman Jerry Lee cared about except for his mother," says a friend. More tragedy followed. His mother died of cancer, and in 1973 Jerry Lee Jr., a 19-year-old aspiring drummer, was killed when he turned over a Jeep on a country road.

"The loss of my mother and two sons got to me," Jerry says. "I was drinking heavy. I needed a fifth of tequila just to sober up. I couldn't cut a record. It wasn't the marriages that brought me down," he adds, his words thick with remembered grief. "It was just the passin' of the caskets." He became vulnerable, friends say, not only to pills and booze but to hangers-on "who wanted to get Jerry Lee wired so he'd pick up their tabs."

"He is very insecure," notes Eddie Kilroy, a Nashville producer. "The only thing he is secure with is his music. He can play Bach, Beethoven. It is God-given. But he runs from everything else. He is terrified of being alone." J. D. Whitten, who was Lewis' road manager for three years, says, "It's especially rough for Jerry at Christmas, Easter, Thanksgiving—the times for family."

Lewis likes to say he has "straightened out" and put his life and career in order. The facts indicate otherwise. Since 1976 he has faced drunkenness or drug charges several times. His domestic situation is complicated. His fourth and sometimes estranged wife, Jaren, whom he married in 1971, lives in a $150,000 Memphis home with their daughter, Lori, 6. But for the past six years Jerry Lee has spent much of his time with Charlotte Bumpus, 24, on his farm in northern Mississippi. He has appeared up on the road occasionally with both women, but friends say that since January he has been living with Jaren again.

To keep everyone happy, Lewis spends profusely. Though he dislikes using cars and insists on flying on trips longer than 50 miles, he owns 20 automobiles. He recently replaced a totaled $40,000 Rolls and bought his 78-year-old father an Eldorado after the old man's Pinto was stolen. Commanding up to $20,000 a night, Lewis can pay the tab but, says Whitten, "He can't retire and live at this level."

The future plainly disturbs Lewis. Last February he spent three and a half weeks in a Memphis hospital because he had "breathing problems" and was hyperventilating. "That got me worryin' about myself," he said backstage after a recent show. Just then a musician broke in, handing Lewis a napkin with an inky message from a female admirer. The letters were staining through the paper: YOUR SOUL WILL GO TO HEAVEN. GOD DOES NOT HAVE ANYONE ON EARTH WHO CAN PLAY PIANO LIKE YOU CAN.

Lewis responded with a slurred soliloquy on salvation. There were no comic overtones, no touches of bravado, of Dixie machismo. There never are when Jerry Lee Lewis speaks of the hereafter. "Salvation bears down on me," he whispered. "I don't wanna die and go to Hell. But I don't think I'm headin' in the right direction. I been lustin' a bit lately. I'm lost and undone, without God or son. I should've been a Christian, but I was too weak for the Gospel. I'm a rock'n'roll cat. We all have to answer to God on Judgment Day." He paused and looked at a visitor in his dressing room. "Me and you, Killer, we'll be standing side by side."