When the jazz pioneer Jelly Roll Morton died penniless and alone nearly 60 years ago, his reputation was already fading. New musical styles had displaced the hot jazz he helped invent, and a younger generation of players disdained him.

Today, however, Morton is resurgent. New books and recordings, together with changing attitudes among scholars, musicians and listeners, are placing him back at the peak of the jazz pantheon.

Part of Morton's appeal, and part of what led musicians in Northern cities like New York to scorn him in the 1930s, was his picaresque and almost unimaginably arrogant style. He wore flashy suits, sported a diamond implanted in one of his front teeth and often told players who were not from New Orleans that their music was pitifully inadequate.

For many years Morton lived the sporting life. He was a larger-than-life figure who made money not just at the piano but as a gambler, pimp, card sharp and pool hustler. Northern musicians like Duke Ellington, including those who emerged from big bands to develop the modern bebop style, dismissed him as a braggart who had failed to keep up with the times and was never as great as he imagined.

'In the 1940s there was a great schism in the jazz world,' said Robert Koester, owner of the Chicago-based Delmark recording company. 'It was the greatest schism since Constantinople. Bebop was triumphant, and the party line was that everything before bebop was junk. The jazz press ignored everything that came before Charlie Parker. That approach lasted for quite a while, but more recently people's minds have broadened quite a bit. One result of that is that Jelly is finally being recognized as a great jazz composer, a great pianist and even a great singer.'

The revival of Morton's reputation grew steadily through the 1990s. Some jazz fans disliked the musical 'Jelly's Last Jam' by George C. Wolfe because, they said, it unfairly portrayed Morton as a racist who denied his black roots and scorned Louis Armstrong. Still, it brought Morton's name and musical style to a new audience, especially in a 1992 Broadway production starring Gregory Hines.

A more authentic tribute to Morton was the two-day celebration of his life and work that was part of the recent Chicago Humanities Festival. At one concert, the Chicago Jazz Ensemble played several of Morton's works that were recently found in a jazz archive after being lost for decades.

As the ensemble played, its founder and music director, William Russo, felt a complex mix of emotions. 'At the simplest level, it was a Tolstoyan delight just to hear this beautiful music wafting through the air,' Mr. Russo said afterward. 'On a professional level, it was amazing to me to hear the quality of this music. Jelly Roll wrote it at the end of his life, and at that moment I was imagining all he would have accomplished if only he'd been able to carry on a little longer. So it was joy mixed with sadness.' Jazz figures like Mr. Russo, who grew up in the 1950s, were entranced by musical innovators like Ellington and Dizzy Gillespie who scorned the New Orleans tradition that Morton embodied.

'The fact that it had been taken over by white boys in straw hats and was advertised as 'Dixieland' sent shivers down our spines, because that was considered racist by many of us,' Mr. Russo recalled. 'Now I see that this is music that gets to you like Shakespeare or Charlie Chaplin, music that is joyous and affirmative but also has real profundity and complexity. Today I would definitely put Morton in the top five of jazz along with Ellington, Louis Armstrong and a couple of others.'

After the ensemble played a newfound piece called 'Gan-Jam,' Howard Reich, a jazz critic who participated in the Chicago tribute, said that toward the end of his life, Morton 'wrote things out as meticulously as Strauss or Beethoven.'

'This is writing that's unbelievably sophisticated,' Mr. Reich said. 'I don't think anyone would ever identify it as by Jelly Roll Morton. It's like a tone poem, written in classical sonata form. It's just an astonishing piece of music.'

Morton enjoyed precisely that kind of acclaim early in his career. Born Ferdinand Lamothe (not Lamenthe or La Menthe, as some earlier researchers believed) into a New Orleans Creole family in 1890, he grew up in a formal musical environment shaped by players at the city's symphony orchestras and opera companies.

By the time he reached his teens, Morton had found his way to Storyville, the city's red-light district, where ragtime musicians played in luxurious brothels, and jazz was beginning to take shape. Whether he actually invented jazz, as he often claimed, is and will always be debatable. Beyond much doubt, however, he was the first serious jazz composer, the first to write multithemed pieces and develop a distinctive jazz style.

Many other musicians who worked in New Orleans around this period also enjoyed great success, among them Armstrong, Sidney Bechet, Buddy Bolden, Joe (King) Oliver, Johnny Dodds, Kid Ory and Tony Jackson, who was the only pianist Morton ever considered his equal or better. Lovers of traditional jazz still revere them all, but only Armstrong and perhaps Morton have risen to the level of musical sainthood.

After a lucrative period during which he became recognized as one of the greatest figures in this new kind of music, Morton began traveling the country, first to learn what styles were emerging in different areas and then to show off his own mastery. In the late 1920s he made a series of recordings at the head of a band called the Red Hot Peppers that still form the bedrock of his reputation. The best of them are available on the Bluebird label under the title 'Birth of the Hot.'

'They are absolute classics, indisputably,' said James Dapogny, a professor of music theory at the University of Michigan who is also a composer, pianist and bandleader. 'They're miracles of organization and artistry. It's not so much that any one person on them is so fabulous, as you might say for Armstrong at the time, but because the way he used an ensemble was absolutely unprecedented.'

Morton worked for much of his career in an environment in which musicians earned their money from performing. For years he did not even consider publishing his scores, fearing that if he did so, others would copy his style, and he would lose his appeal. Few of his scores were available until 1982, when Mr. Dapogny published a painstakingly transcribed collection that helped spark the Morton revival.

Another factor that led a new generation to discover Morton was Rounder Records' release in 1993 of four astonishing discs he recorded in 1939 (Actually May 1938. B.W.) for Alan Lomax, then an archivist at the Library of Congress and later author of a biography of Morton that is to be reissued in the spring.

The Library of Congress recordings are re-creations of the music Morton performed in his youth, some of it profane and much of it gorgeously improvisational. Few who hear these discs fail to be awed.

'Talking about Morton's greatness, there are several subgroups,' Mr. Dapogny said. 'If you only heard the piano solos he recorded in 1923 and '24, you'd say he was doing stuff nobody else was doing. If you only saw his music on paper, you'd say it was not like anything any of his forerunners wrote because it has a depth of thought that doesn't exist in earlier jazz or ragtime. If you only heard his band music, you get this sense of how perfectly he used an ensemble. And if you only hear the Library of Congress sides, you see what a fabulous improviser this guy was.'

Morton's later years were heavy with disappointment. Like many musicians of color, he was denied membership in Ascap, the organization that collects royalties for composers. Oddly, Ascap did collect royalties on his music but never turned them over to him. Publishers who distributed Morton's later sheet music, notably the Chicago-based Melrose brothers, also cheated him out of his financial due. He wrote dozens of protest letters to state and federal prosecutors, but got nowhere.

At one point, drawing on lessons he had learned as a boy in New Orleans, Morton concluded that enemies had placed a voodoo curse on him. He claimed to have found magic dust scattered in his office and at one point burned all his clothes in an effort to drive away evil spirits he believed were tormenting him.

In his later years Morton conceived the idea of setting up bands in various cities to play his music, but a lack of money left him unable to realize this ambition. He moved to Washington and found work as a host and bouncer at a disreputable nightclub. After a disgruntled customer stabbed him in a fight, his health began to decline.

In a final bid to recover his lost reputation and prosperity, Morton moved to Los Angeles. Several film producers are said to have expressed interest in featuring him or his music, but he died in July 1941 with those plans unfulfilled. No film clips of him are known to exist.

Today many jazz scholars agree that Morton was a dominant figure in creating this form of music, said Bruce Raeburn, curator of the Hogan Jazz Archives at Tulane University.

'He's now generally cited as the first great composer in jazz history, and I don't think many scholars would disagree,' Mr. Raeburn said. 'The correlation is with Ellington, and some of us actually prefer Morton. Not to take anything away from Ellington, but I just have more fun with Morton's orchestrations. His artistry is just so interesting.

'Morton took a kind of rough communal music based in New Orleans, then polished it and created a coherence that had never been there before. He was extremely flamboyant as a composer and arranger, but it always works. Pieces like 'Black Bottom Stomp' are like Faberge eggs, full of tricks and layers, with time changes, coloration and texture.'

Morton's rehabilitation is beginning to extend beyond academe and concert halls into jazz clubs and popular recordings. When young musicians like Reginald Robinson, 28, one of Chicago's leading jazz pianists, perform Morton's music, they pay him a homage that is the opposite of the disdain heaped on him by the bebop generation.

'I think there really is a rediscovery going on, especially among younger musicians,' Mr. Robinson said. 'For years I heard negative things about Jelly Roll Morton and his background. Willie (the Lion) Smith used to call him 'Mr. One-hand.' But when I started listening to him, he just knocked me out. I mean, which hand was Willie talking about? No way!'

'I'm one of those guys who has realized that Morton was a fantastic composer and musician, one of the real pioneers of jazz,' Mr. Robinson said. 'He's very, very important. I'm finding that out.'