By Ashley Kahn, Special to MSN Music

There's always been a lot more than jazz at the New Orleans Jazz & Heritage Festival.

Take a gander at what's in store when the world-renowned celebration kicks off its 37th year on April 28: Bruce Springsteen, and hand-clapping gospel choirs. Dave Matthews, and house-rocking R&B groups. Juvenile, and street-marching Mardi Gras Indians. Fats Domino and Keith Urban and Paul Simon and Lionel Richie and Bob Dylan.

Which is to say there's also a lot more heritage than jazz at the festival -- no complaint because "heritage" includes the best blues, gospel, Cajun and street-parade music the region has to offer, in addition to the usual wide array of rock, soul and, yes, jazz styles. Place all that music outdoors -- 375 bands total on 10 stages -- amid warm Southern breezes and generous servings of Louisiana cuisine (a lot of rice and spice), and it adds up to one thing.

New Orleans' jazz festival is, quite simply, America's best party -- certainly its most musically diverse. It's been like that since the first festival was held in 1970 and has grown in popularity from a few hundred who attended that year to an international draw that temporarily increased New Orleans' population by 400,000 in 2005.

But this year, in the wake of Hurricane Katrina, things will be markedly different. The circle of New Orleans musicians has been broken and scattered, while the essential resources for an event of this magnitude -- water, power, funding -- were uncertainties until only a few months ago. To some, it might seem that other projects in the region might take precedence, even if Jazz Fest helped New Orleans net close to a quarter of a billion dollars last year.

But to those raised in this city with its own set of cultural priorities, Jazz Fest (as it's called locally) is more than economic impact; it's part of the rhythm of life itself. "There's just a certain energy in the air when it's Jazz Fest," says internationally celebrated trumpeter Nicholas Payton. "It's like Mardi Gras, but more like Christmas -- like a big family reunion of people from all over the world, musicians and nonmusicians. You start gearing up for it, and you know it's that time of the year."

To understand how Jazz Fest came to be the seasonal ritual it is today, it's helpful to take a brief look at the history of the festival phenomenon.

In 1953, George Wein, a Boston jazz club owner, developed the novel idea of moving jazz from the smoky confines of nightclubs to an al fresco, summertime setting. Artful negotiations secured a hallowed tennis club in nearby Newport, R.I., plus an A-list of jazz talent including Billie Holiday, Dizzy Gillespie, the Modern Jazz Quartet, Ella Fitzgerald and others. One long July weekend later, national headlines proclaimed the birth of a new kind of event, as publications such as the Saturday Review wrote that "jazz goes well, as it should, with sea, air, trees, history, and the haut monde ..."

The Newport Jazz Festival engendered a monde of its own. By the early '60s, similar festivals had sprung up in various American cities and in Europe, while Newport added a similar festival focusing on folk music. In the late '60s, groundbreaking outdoor festivals in Monterey, Calif., and Woodstock, N.Y., translated the idea for the rock generation. Newport itself began to expand its programming to include rock, funk and other styles that were jazz- and blues-connected.

In 1969, the same year as Woodstock, Wein was introduced to Quint Davis and Allison Miner -- a pair of idealistic teenagers in New Orleans, who were tied into the city's vast and varied musical scene. Together, they would become the production engine behind Jazz Fest. Davis credits Wein for the festival model that still holds sway today.

"The current New Orleans Jazz & Heritage Festival was George's concept and vision ... he insisted on a traditional-music, multi-area ethnic event, like [folk music legend] Pete Seeger had initiated at the Newport Folk Festival," Davis says.

That first Jazz Fest was held in the city's historic Congo Square (now Armstrong Park) abutting the French Quarter, where the rhythms of slave dances could be heard on Sundays more than a century before. Davis recalls:

"At that first festival, [gospel singer] Mahalia Jackson had done a night concert, and she came out to the fair at Congo Square one afternoon just to check it out. And she got fired up and spontaneously started singing 'Just a Closer Walk with Thee' with [trumpeter] Percy Humphrey and the Eureka Brass Band.

"To me that was the eternal spark of what the whole festival was forever going to be about." From that point, the festival developed so rapidly that Davis and company had to find a new home with the necessary acreage. They found it in the inner oval of a local racetrack. In 1972, Jazz Fest moved to New Orleans' Fair Grounds and expanded its food, workshop and craft programs. And those magical, musical moments became a regular thing.

Howlin' Wolf, Dave Brubeck, Rhasaan Roland Kirk and B.B. King all performed in '73. That same year Stevie Wonder sat in with local funk stars The Meters. Wonder returned in '77 to sing with Ella Fitzgerald. By its 10th anniversary, Jazz Fest had already reached its current size, duration and reputation.

In the years since, Jazz Fest has hosted an expanding variety of headliners: Carlos Santana, James Brown, Stevie Ray Vaughan, Al Green, Bonnie Raitt, L.L. Cool J -- as well as local sons Wynton Marsalis, Harry Connick Jr. and the Neville Brothers. Meanwhile, the festival drew an annual flood of national and international guests. A substantial number were returning music lovers, hopelessly hooked on the Mardi Gras Indians, the gospel tent and the tongue-singeing food.

Today, when other well-known, under-the-sky celebrations, such as Bonnaroo and Ozzfest, tightly focus on a jam-band or heavy-metal audience, Jazz Fest draws a generously wide demographic. And once the sounds have ended for the day at the Fair Grounds, the city itself takes over: It can seem like every New Orleans nightclub and bar -- even bowling alleys -- will have a live band performing.

"Places that don't have music usually will have music during Jazz Fest," adds Payton. "You have all the regular spots like Tipitina's, Snug Harbor, Donna's Bar & Grille, the Funky Butt. And you have all these neighborhood places and they all have music and every one of them is packed."

Sleep becomes an option after a day filled with must-see shows at the Fair Grounds is followed by nights of the same around the city. The primary challenge becomes deciding what not to hear. "Should I see piano master Allen Toussaint or catch soulful bluesman Walter 'Wolfman' Washington? The hard-driving rhythm-and-blues of Ike Turner or the reunion of the original Dirty Dozen Brass Band. Or Elvis Costello?" (Take my word for it, it's tough: These acts all performed within two hours of each other one Saturday last year.)

"That's what's special about it," adds Payton. "At other festivals, when the festival is over, it's over. In New Orleans when the festival is over, it's just beginning."

Lest this description seem like too much hagiography, I should add that there's always been room for improvement and that Jazz Fest continues to challenge itself year after year. There's been the ever-contentious issue of how many festival slots should be reserved for local artists and how Jazz Fest profits should be distributed (Jazz Fest is produced by Davis and Wein, who are hired by a foundation with a rotating membership). In 2004, rain kept scores of people away, and an imprudent aversion to saving funds against potential losses brought Jazz Fest its first profitless year.

It was a wake-up call that came just in time. Changes had already been made when the hurricanes of last August hit. Davis and Wein continue to produce the festival in a fashion that can help it survive -- and help heal the city as well.

One doesn't need to mention Katrina when in New Orleans. It's already a primary part of almost every conversation in the city; songs about Katrina have been written, recorded and will be heard loudly at Jazz Fest. Fair Grounds attire this year will certainly include T-shirts currently on sale in the French Quarter, like the one reading "Katrina and Rita: Those Crack-head Bitches!"

With more filtered vocabulary, Davis speaks of his hopes for a full recovery, calling Jazz Fest 2006 "the most important Jazz Fest in history ... a homecoming party for thousands of New Orleans musicians, festival chefs and craftspeople, and we want the world to join us in welcoming them back as we present the celebration of a lifetime.

"Anybody who comes to this year's festival will bear witness to the healing power of music."

Ashley Kahn is an American music historian, journalist and producer. He has toured as road manager with artists such as Henry Threadgill, Cassandra Wilson, Greg Osby, Ladysmith Black Mambazo, Hugh Masekela, Lucky Dube, Paul Simon, Peter Gabriel and Britney Spears. Kahn has also written books about two essential jazz albums: Miles Davis' "Kind of Blue" and John Coltrane's "A Love Supreme." His writing has appeared in the New York Times, Downbeat, Jazz Times, Rolling Stone, Mojo, New Statesman and GQ; he's also a regular commentator on NPR's Morning Edition.