Though Isaac Hayes has not had a hit single in almost 20 years, and has not even released an album since 1988, he is still recognized in the Marriott hotel in Greenbelt. Awestruck guests and employees alike make quick pilgrimages through the lobby to greet the barrel-chested "Black Moses." A quarter-century past his "Theme From Shaft," Hayes's beard is lightly salted with gray, but his bold, bald dome glistens as it always has.

Fans slap hands with him, timidly ask for an autograph, mention some tenuous long-ago connection -- and all the while, Hayes, 53, beams, because this part of it has remained as sweet and constant as the Sam & Dave classics he penned with David Porter in the '60s.

"Thank you, darlin'," he says to one fan, speaking in the deep, mellifluous baritone that once asked: "Who's the black private dick who's a sex machine to all the chicks?"

He's so much more than "Shaft," though.

When Hayes became the first black music superstar of the '70s, he was embarking on the public phase of a career already notable for its achievement behind the scenes at Memphis's Stax Records. Writing for and producing Sam & Dave, Hayes and Porter scored chart successes -- and established pop culture signposts -- with "Hold On, I'm Coming," "I Thank You" and "When Something Is Wrong With My Baby." Their "Soul Man" would become an anthem during the black consciousness movement of the late '60s.

When Hayes's own "Hot Buttered Soul" album was released in 1969, it turned him into a cultural icon and set the stage for changes in the singles-oriented black music market. "Hot Buttered Soul" spurred black album sales with its extended tracks, its spoken message stories and romantic rhapsodies (precursors to both Barry White and rap), and its breakthrough meld of classical strings, funk guitar and propulsive rhythm tracks (did somebody mention disco?).

And success begat extravagant road shows, with Hayes, dubbed Black Moses, leading a 50-strong cast of musicians, singers and dancers.

But by 1976, Isaac Hayes was bankrupt, thrice divorced and riding the roller coaster in another direction. And though he would make a dozen albums after leaving Stax in 1974, none would have the impact or the commercial success of his earlier work. Part of the reason, Hayes concedes, was shifting tastes, and nowhere do they shift more quickly than in black music.

But, he suggests, the music industry also bore some responsibility.

"It let us down," he says -- "us" being veteran black artists. "The Rolling Stones, Eric Clapton, people like that, they're not forgotten. They're in their fifties and still gigging and touring. When we get to 30, we're suddenly too old and they just kick us aside."

And adding ignominy to injury, "when you go and seek a contract and you have to talk to a young A&R {artists and repertoire} person who has no idea about your musical history, the first thing they ask is Mr. Hayes, what have you done lately? Can we hear something?'

"And I want to say so damn badly, Turn on your radio and listen to the rappers. That's what I've done lately.' But I just get up and walk out."

If that A&R person had heeded Hayes's counsel, he might have heard the Geto Boys's recent "Mind Playing Tricks on Me," built on a sample from 1974's "Hung Up on My Baby." Or Public Enemy's "Black Steel in the Hour of Chaos," which sampled "Hyperbolicsyllabicsesquedalymistic." Or the bass line from "Ike's Mood," sampled by Dee-Lite, Portishead and Tricky. Between the hip-hoppers and trip-hoppers, Hayes was sampled on more than 40 tracks last year alone -- but he couldn't get a record contract.

Until John Wooler, a British fan who heads an American label, showed faith in Isaac Hayes. Wooler's roots-oriented Pointblank records (the label, specializing in black roots music, is part of Virgin) recently released two new Hayes albums, "Branded" and the all-instrumental "Raw & Refined."

"In England, people understand that blues and R&B are the root of rock-and-roll as we know it; here, people take it for granted," says Wooler. "The music industry has pushed a lot of musicians aside, even those with Isaac's kind of stature, not believing or having confidence that they can still make great records.

"He sold millions of records being Isaac Hayes, so why make him sound like some '90s dance-rap artist?" Wooler adds. "What's the point?" 'The Ladies Were Crying'

Before he became Black Moses, Hayes was a part of such Memphis acts as Sir Isaac & the Do-Dads, the doo-wop Teen Tones and the Morning Stars, who broadcast live from Pleasant Green Baptist Church every Sunday. Hayes even sat in with jazz bands. He was still in high school at the time, consumed by all kinds of music in a city that was a cultural crossroads long before Elvis Presley arrived.

Graduating with a few talent-show wins under his belt, Hayes was offered music scholarships to several colleges; instead, he went to work in a meat-packing plant to support his pregnant wife. When he and keyboardist Sidney Kirk heard a studio was opening nearby, they auditioned and signed up.

"Laura, We're on Our Last Go Round," released in 1962 on Chips Moman's short-lived Youngstown label, would be Hayes's first single. "It was like Neil Sedaka," he recalls. "Pure rock-and-roll with strings. We sold about three copies, but I was a hero in the neighborhood."

The following New Year's Eve, Hayes was talked into subbing for Kirk at a party, even though he "didn't know much beyond Chopsticks' and Heart and Soul.' " Luckily, the band was drunk, as was the audience and club owner, who promptly offered Hayes a regular job. "So every night I learned something on keyboards, and that's how it got started."

Hayes eventually joined the band led by Floyd Newman, a baritone saxophonist on the staff at Stax Records, which was beginning to make a name for itself as "Soulsville," the South's gritty answer to Motown's "Hitsville, USA." He started hanging around the Stax studio, and when Booker T. Jones went off to college, Hayes got a chance to replace him on keyboards. His first sessions were with Otis Redding, and it is Hayes's organ and arrangement that define Redding's "Try a Little Tenderness."

The Studio A piano was the crucial gathering place at Stax -- "That's where we worked up the tunes before we went to our respective cubbyholes," Hayes explains. Nothing was written out except for lyrics -- it was all "head arrangements," with Hayes calling out the chord changes and tempos and pulling things together on the spot with the Stax house band -- Booker T and the MGs, the Memphis Horns or the Mar-Keys. It was a process that resulted in hit after hit.

"Isaac didn't read, but you couldn't believe a guy could sit at a piano and come up with the sounds he did," says Sam Moore of Sam & Dave. "When people talk about the Memphis sound, that was Isaac."

Moore and his partner, Dave Prater, would become beneficiaries of some of Hayes's best work, particularly after Hayes teamed up with lyricist David Porter. The two had been high school rivals ("I sang with the Teen Tones, he sang with the Marquettes"), but at Stax they became a dynamic duo.

"Double double dynamite," Moore says with a laugh. "The chemistry between those two was phenomenal." Tailoring their material to Sam & Dave's gospel-rooted dynamics, Hayes and Porter began a string of hits in November 1965 with "You Don't Know Like I Know," peaking in 1967 with the chart-topping "Soul Man."

They also scored major hits for Carla Thomas ("B-A-B-Y"), Mable John ("Your Good Thing Is About to End") and Johnnie Taylor ("I Got to Love Somebody's Baby"). It's the Sam & Dave classics that remain vibrant in the pop lexicon.

Some of those classics had humble beginnings. "Hold On, I'm Coming" was Porter's response to Hayes yelling at him to hurry back from the bathroom during a recording session. "I had a groove going and I was getting impatient. . . . And David said, Hold on, I'm coming . . .' And that was it: He came running out of the restroom pulling up his pants, saying, That's it, I've got the title!' "

"Soul Man," on the other hand, was inspired by news reports from the 1967 race riots in Detroit and other northern cities. "If you put Soul' on your door, {looters and arsonists} would bypass it, like with blood of the lamb during the days of Passover," says Hayes. "And so we extrapolated that as pride -- I'm a soul brother, I'm a soul man."

Hayes was favored as a writer and producer, but not as a singer: The head of Stax considered his voice "too pretty" for the gritty soul stew for which the label was famous. But after many bottles of champagne during a birthday celebration one night at the studio, Al Bell, then head of Stax promotion, rolled the tapes. "I commandeered Al Jackson on drums and Duck {Duncan} on bass and said, Y'all follow me,' " says Hayes. "It was definitely impromptu.

"Two weeks later, Al Bell told me I had to pose for the cover because the album was coming out."

The album, "Presenting Isaac Hayes," didn't sell well. But, Hayes points out, it "had some jazz flavor to it, some funky blues. In fact, when you look at it overall, it was prelude for what was coming."

What was coming arrived two years later in the form of "Hot Buttered Soul," and once again Bell (by then president of Stax) was involved. Bell had signed a deal with a major investor, boldly promising to release 27 albums at once.

"He needed catalogue," says Hayes, who agreed to help out in return for production carte blanche. "I didn't give a damn if Hot Buttered Soul' didn't sell, because there were 26 other LPs to carry the load. I just wanted to do something artistic, with total freedom. And I couldn't say what I wanted to in two minutes and 30 seconds."

Hayes had already elongated "By the Time I Get to Phoenix," the Jimmy Webb-penned Glen Campbell hit, testing it out at the Tiki Club, a Memphis nightspot with an audience as demanding as any Apollo Theatre crowd. "I had to capture their attention, and necessity being the mother of invention, I started talking, setting up the song, looking at what led to the breakup of a couple . . . until it got very quiet," Hayes recalls. "And the ladies were crying when I finished."

The 18-minute "By the Time I Get to Phoenix" and a 12-minute "Walk On By" quickly became late-night FM favorites. In both songs Hayes incorporated his fascination with strings, which dates back to when he saw the Memphis Symphony Orchestra as a child.

"I'd heard fiddles on the Grand Ole Opry but not that power or discipline, all these people moving at the same time," says Hayes. "And in high school music appreciation, I'd heard Bach, Beethoven, Grieg, Debussy and, damn, they were really doing some wonderful things. I absorbed them all and wanted to use them somewhere. I tried with Sam & Dave, did a whole album, but it flopped, people didn't accept it. But I never gave up on the idea." It would be the Memphis Symphony that provided the strings on "Hot Buttered Soul."

Hayes's symphonic soul approach was very different from mainstream R&B, but it broke through in a big way: "Hot Buttered Soul" sold more than 1 million copies at a time when black album sales rarely climbed so high.

But Stax was having serious financial problems, and the relationship between Hayes and Porter became strained. In 1971, the pair split up.

"After Hot Buttered Soul,' we just didn't have any more time to write," says Porter, who now heads the Memphis chapter of the National Academy of Recording Arts and Sciences and operates his own publishing company. "I would have been crazy to not want us to keep working together, but I encouraged Isaac to go on, make the money. I was happy for him."

"We just went our separate ways," acknowledges Hayes. "I was jerked away by success."

That success was due in part to Hayes's soundtrack for Gordon Parks's "Shaft." Hayes had never scored a film, and when it was time to score the opening scene of Detective John Shaft coming out of the subway, he dug into his vaults for a bristling hi-hat lick that Al Jackson had played on the break in "Try a Little Tenderness." He paired it with an old "wah-wah" guitar vamp played by Charles "Skip" Pitts.

"They said Shaft was a relentless character, and it had to denote some kind of action or drama," Hayes remembers. He recorded it in two hours.

A year later, a bare-chested Hayes, his torso draped in chains, was in Hollywood, bursting through the floor at the 1972 Academy Awards ceremony, performing his "Theme From Shaft," and returning to the podium soon after -- this time wearing an ermine-trimmed outfit -- to accept the Oscar for Best Original Film Score.

Once again, he had recorded with his unconventional method of arranging. Initially, the Academy of Motion Picture Arts and Sciences tried to disqualify him because the "Shaft" score wasn't written, but Quincy Jones argued his case and proved convincing. 'Get Up in a Hurry'

Hayes used to have mixed feelings about the nickname "Black Moses," which started as an item in Jet magazine and quickly became an art and marketing coup for Stax. "I was uneasy about the term Black Moses until I understood what it meant to the people," he says now, acknowledging that the image -- equal parts prophet, warrior and lover -- represented both liberation and sexuality.

"When I realized the relevance that it had," he adds, "I realized I had to live up to it, stay clean and responsible."

Hayes left Stax in 1974; two years later, both he and the label filed for bankruptcy. "The thing that bothered me the most about the bankruptcy was I hoped that the aspiring young black kids would not be discouraged because Isaac Hayes stumbled and fell," he says. "I had to get up for me and for them."

The IRS auctioned his Memphis estate, the gold-plated limo, the designer furs, the monogrammed soap. "The day they were liquidating me, I was in the studio working on my next album -- New Horizons.' If you don't get up in a hurry, you might not get up at all."

During the '80s, a time he describes as "somewhat of a blur," Hayes turned to acting. "The music industry had turned me out to pasture, but the movies kept me eating. Thank God I had more than one hat to wear."

Film roles had actually started coming his way in the mid-'70s ("Truck Turner," "Three Tough Guys" and later, "Escape From New York"), as did television parts on "The Rockford Files," "Starsky and Hutch" and, later, "Miami Vice" and "Hunter." And Hayes has continued to work in film: He will appear in next summer's "Flipper" remake, and is reuniting with "Shaft's" Richard Roundtree in Tim Reid's upcoming "When We Were Colored."

Hayes's second musical wind got a boost from an unlikely source.

"One of my teenage sons started playing this song, and part of it was the bass line of Walk With Reggio' from Shaft,' " he explains. "I said, Son, do you know you're listening to your old man?' "

Then last year, the Geto Boys had a No. 1 hit with "Mind Playing Tricks on Me," using a sample from Hayes's "Hurry to My Baby." That, says Hayes, was "a wake-up call," followed by a call to the company that administered his copyrights. Soon after came the call from Pointblank's John Wooler.

On his new "Branded" collection, Hayes gives Sting's "Fragile" a full-blown, 13-minute arrangement. He updates "Soulsville," the still-potent snapshot of urban decay from "Shaft," and revives "Hyperbolicsyllabicsesquedalymistic" with a little help from Public Enemy's Chuck D, who had previously sampled it.

And, for the first time in almost a quarter of a century, Isaac Hayes wrote with David Porter. "Thanks to the Fool" sounds like vintage Hayes-Porter soul.

"We met at a luncheon in Memphis and just talked," says Hayes. "I gave David the title and he wrote the lyrics, and a few days later we cut it. We fell into the pocket right away, he was right there. It was like old times." CAPTION: Isaac Hayes has two new albums that he hopes will introduce a new generation of fans to his music. CAPTION: The songwriting team of Isaac Hayes and David Porter, above. "When people talk about the Memphis sound," says Sam Moore, Porter's partner onstage, "that was Isaac." Below left, Hayes accepts his Oscar for "Theme From Shaft' "; and makes his film debut, below right, in 1974's "Three Tough Guys."