The Art Show is the sober adult at the seemingly endless homecoming weekend staged by dealers and collectors for the contemporary art market.

Opening Thursday at the 7th Regiment Armory, the dignified fair is older, at 18, than its main American rivals, the Armory Show and Art Basel Miami Beach, both of which are bigger, brasher, and intently focused on the here and now. With 70 galleries participating, the Art Show is one-third to one-half the size of these fairs, and more tethered to home.

The galleries assembled in the soaring Park Avenue armory all belong to the Art Dealers Association of America, which runs the fair and takes as its mandate the promotion of good conduct and solid scholarship. (In other words, no phonies and no fakes.) These dealers are mostly New Yorkers, although they sell art made all over the world. Several New York dealers participate in both the Art Show (which is in the Armory) and the Armory Show (which is not).

“We can’t compete against Basel Miami and Frieze and these shows,” the chairman of the Art Show, Roland Augustine of Chelsea gallery Luhring Augustine, said. “What we can do is to work closely with members, help them develop a more curatorial eye, and vet things as closely as we can and to raise funds for Henry Street.” Henry Street Settlement is the charity for which the opening party, being held tomorrow night, annually raises about $1 million.

Small, of course, can be beautiful. “It’s more of a niche fair,” Mr.Augustine said.”Because of its intimacy, it has a particular appeal and draw. It’s not hectic and frenetic.”

The Art Show had 12,000 visitors last year. Sales may approach $20 million to $25 million, Mr. Augustine said. The Armory Show, which opens March 9 with 154 international dealers at the Hudson River Piers, claimed 40,000 visitors in 2005 and more than $45 million in sales. Art Basel Miami Beach doesn’t release sales figures, but it drew 36,000 visitors last December.

“The ADAA differs from the Armory because you can bring blue-chip works,” said Carla Chammas, co-director of Chelsea’s CRG Gallery, which has booths in both fairs. The gallery is focusing its booth on the theme of materiality, with works available by Lucio Fontana, Bruce Conner, Piero Manzoni, and the gallery’s contemporary roster, ranging from $15,000 to $600,000. “The uptown show brings in people from a 20-block radius. It has a more upscale, uptown collector,” Ms. Chammas said.

“People buy things to keep – those are your best clients because they’re called real collectors,” said dealer Linda Hyman, who is bringing works by several Abstract Expressionists, including Jack Tworkov and Milton Resnick, priced between $50,000 and $150,000. “There’s something very New York about it.” Dealer Barbara Mathes will feature a Jackson Pollock work on paper, as well as a 1955 Joseph Cornell box.

“It’s an art fair for connoisseurs,” said Mary Sabbatino, vice president of Galerie Lelong, which is bringing a photograph by Andy Goldsworthy, a map drawing by Jane Hammond, and several works by Spanish installation artist Jaume Plensa. The gallery, which also participates in the Armory Show, has previously brought to the Art Show more classic modern drawings by Miro or Giacometti. But the demand for contemporary art at the fair is on the rise, according to Ms. Sabbatino. “The atmosphere is geared in terms of scale and location to sell beautiful modern or rarer works. But I think the fact that contemporary is selling well is a function of the interest in contemporary,” she said.

The preference for contemporary above all else has not gone unnoticed by fair organizers, who have made efforts in recent years to invite more galleries that focus on newer works. “It’s a function of there not being as much material,” Mr. Augustine said of the dwindling numbers of Old Masters and modern dealers. “Go out and find a great Hopper – it’s impossible, so naturally there’s been more of an emphasis on contemporary.”

Chelsea gallery Lehmann Maupin, which represents Tracey Emin and Dohuh Suh, is one of the newcomers this year. “We perceive the ADAA as smaller, more focused, a serious fair with serious collectors,” the gallery’s sales director, Courtney Plummer, said. “There’s a little less browsing and cruising than you see at the Armory.”

The gallery is devoting its booth to new works by Teresita Fernandez, who recently won a MacArthur Foundation award. Three weeks later, it will set up shop at the Armory.”We’ll see the same people in one month,” Ms. Plummer said. “It’s just that there are so many collectors now buying.”

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In addition to its genteel size and atmosphere, the Art Show is distinguished by the fact that it features only American galleries.That poses a potential marketing problem. As the fair gains more contemporary dealers, its regionalism conflicts conceptually with the frequent-flier-enhanced lifestyles of the culturati. Contemporary art is a global language, shared among those who can speak with equal fluency of Jean Prouve, Jean Baudrillard, and James jeans.

Most art collectors and dealers see themselves as consummately cosmopolitan. Who saw whom on flights to London, Miami, and Maastricht counts as substantive conversation. The Whitney Biennial, which opens March 2, has for the first year, dispensed with nationality as an exclusionary criterion, letting in an Italian (Francesco Vezzoli), a German (Florian Maier-Aichen), and a Frenchman (Pierre Huyghe).

Mr. Augustine said he realizes internationalism, however vaguely defined, has its place in the future. “I would like to see an engagement with international galleries at some point that would accrue to both international and ADAA communities.” But the ADAA as such is still relevant, he said. “In a nonregulated industry such as the art industry, it’s important that there’s an association such as the ADAA saying we are interested in ethics and connoisseurship.”

The Art Show 2006 will be open February 23, 24 & 25 from noon to 8 p.m., and February 26 & 27 from noon to 6 p.m. at the 7th Regiment Armory (Park Avenue at 67th Street, 212-766-9200). The inaugural gala will be held February 22 from 5:30 p.m. to 9:30 p.m.