Dirty-Down <i> by Peter Clothier (Atheneum: $17.95; 320 pp.) </i>

Late last fall, with the opening of the County Museum’s Robert O. Anderson Building and the Museum of Contemporary Art downtown, legions of bemused cosmopolites discovered the L.A. art world in much the way that Columbus “discovered” the Indians. Now, as fresh as last November’s headlines, comes a moderately engaging, but poorly crafted art world mystery from Peter Clothier, former dean at Otis/Parsons. The whiff of art world roman a clef is an incentive for local readers.

“They had started out together in the late fifties, fresh out of Chouinard,” Clothier writes of his principal characters: “Leon, Wil, and Stu Ray, a threesome.” Late-’50s Chouinard, one recalls, included Larry Bell, Joe Goode, Ken Price, Ed Ruscha, and their classmates. Roland Reiss attended UCLA, but it is his work that the author appropriates for Wil: “pieces on the floor . . . in plexi boxes, thigh-high, so that you had to look down into . . . that teasing play of images in ‘mysteries’ that he never fully allowed to tell the whole story.”

“ ‘Art world is a tiny one,’ ” Wil tells the police after the novel’s second murder. “ ‘We’re talking two hundred fifty folks, a hundred fifty of them friends.’ ”

Welcome to that tiny world of artists, dealers, critics, collectors, curators, conservators, registrars, and warehousemen. Welcome but beware the likes of Leon Drake. Leon invests in Venice real estate. Driving prices higher, he reinvests in art--a Matisse, a Delaunay, a Kandinsky, two Monets--all of it priceless and all of it pilfered through forgeries returned to unsuspecting lenders of originals and transit thefts. His rapaciousness, more than matched by that of others, engenders deadlier crimes.

What have the artist and detective in common? “What hooked (Wil Garretson), pushed him farther than he’d planned to go, was the simple urge to get the problem solved--an instinct that governed every artist’s work. Once the gears are meshed, their action takes a life of its own.”

From the moment we are misdirected to Leon and Stu Ray as prime villains, “Dirty-Down” becomes genuinely, if intermittently exciting. But for an art world expose, the close-ups come in all the wrong places: “Leon spun the Corvette back across the gravel, crashed into first and squirted rocks from under the tires. . . . He took his foot from the brake, changed up, brought his foot down onto the gas pedal”--and so on and so forth.

I hope my job will be there tomorrow if I reveal to you today that writing about art is generally bad; about the art world, generally better, the journalists having a leg up on the art historian/curators. The journalists write more often and are paid on the basis of how well they do it, though there’s always something faintly fishy about their scholarly credentials. Curators have the finest credentials, but for most of them, writing is merely an onerous job requirement, and, as writers, by some perverse alchemy, they turn gold into lead.

Clothier is somewhere in between. His novel has plot and atmosphere, but his style is atrocious. The cliches--”He looks as tough as nails, but underneath, he’s strung together with high-tension wire”--are numbing, and the mixed metaphors dizzying: “There it was again. Freeze frame (that’s one) then action. A kind of visual itch (that’s two) that eclipses (three) the noise and activity of the opening-night crowd. . . .”

Clothier is best when he digresses. That’s when he reveals the art world plausibly. “The damn collectors bitch about the way we handle their precious goddam stuff,” a handler complains, “but they don’t know enough to take care of it themselves,” which is followed by a disquisition on the proper wrapping of paintings for transport. A chapter on an art forger at work leads to a discussion of underpainting in abstract expressionism, of gestures made, painted out, and reconfigured. There are interesting observations about the local gallery business: “Downtown--that scene’s old hat, and MOCA doesn’t seem to be helping the galleries there, like it was supposed to. The ones that opened up a couple of years ago are closing their doors already”; “successful dealers (have) something going in the back room--primitives, some of them, or designer contracts. There was one who dealt in erotica on the side.” And finally this: “ ‘Remember, the early seventies? It all had to do with values, when you get down to it. The funny thing is, it was all an act . . . but you had people lining up to join the game. Falling all over themselves to buy whatever anyone said was art. And don’t say the artists didn’t join in, too. They loved it. There’s so much trash around and so much that looks alike. So much that’s phony--and so few who care about the difference.’ ”

Clothier knows much about the difference, but only some of what he knows has found its way into his novel.