RESTAURANTS : THE IVY LEAGUE : Few Restaurants Have Survived as Long or as Successfully as This Westside Hangout.

Nobody gets a copy of the cardboard-framed, floral-fabric-swathed bill of fare at Richard Irving’s restaurant, the Ivy in Los Angeles--not faithful customers, not souvenir hunters. Nobody takes photos at the Ivy, either--not even snapshots at birthday parties.

Irving forbids photography, he says, to safeguard the privacy of his guests, celebrated and otherwise (and there are plenty of the former). Irving and his partner, decorator-antique dealer Lynn von Kersting, also own the Ivy at the Shore in Santa Monica, where the same rules apply.

Nevertheless, the Ivy has been one of the city’s great restaurant success stories. Originally sharing space with an upscale pastry shop called L.A. Desserts in 1980, it was a modest cafe with a handsome brick patio on Decorator Row. Named in honor of the Hedera helix that frames the patio, it was sort of a contemporary California tearoom at first, where a puff-pastry “pizza” was one of the hits. After a promising few months, it expanded, and its menu grew more serious. It remains among the busiest places in town, drawing a clientele of Hollywood moguls, decorators and designers and just folks looking for good, hearty food and a glimpse of glamour.

Maybe, it occurs to me when I consider his success, Irving is so protective of his menu simply because he doesn’t want to see his formula ripped off.

Well, fair enough, I guess. But in fact, it would be pretty easy to imitate the Ivy, quite without aide-memoire. It’s all pretty basic. The decor is an attractive clutter of antiques, bric-a-brac and folk art. The oversized plates are Italianate painted earthenware. Service is efficient and friendly without being presumptuous; special requests and minor glitches are dealt with skillfully and quickly. Apart from tandoori chicken and the inevitable pizzas and pastas (which lean slightly more toward Italy than toward Spago), the menu is mostly straightforward all-American with a Louisiana flavor.

Irving was perhaps the first local chef outside the black community to serve Cajun-style dishes and to specialize in Louisiana seafood. Today, his fish and shellfish can be glorious in their freshness and simplicity, such as a serving of seven oysters on crushed ice; a massive stone crab claw, chopped into pieces and cracked, the meat moist and sweet with a tang of seawater; superlative soft-shell crabs, tiny and genuinely soft, lightly sauteed and glistening with lemon butter; delicious Louisiana shrimp (though not quite enough of them) in a dark, sweet onion-based sauce, spicy with black pepper, spooned around white rice.

Fresh shrimp appear less successfully in other forms, such as a salad in which they are poached and set against arugula dressed with vinaigrette, and the pungency of greens and dressing just about kills them. Mostly, though, the food at the Ivy is just right. It’s not very refined or innovative, but it’s based on first-rate raw materials, is well-cooked and (shrimp aside) is served in ample portions--as it should be, considering the ample prices.

Pizza--topped, for instance, with sun-dried tomatoes, fresh mozzarella and parmigiano cheese--is thin and sizzling. Very good homemade tagliarini noodles are served in several preparations; one, with garlic, porcini and wild mushrooms, was particularly satisfying. Cajun prime rib is serious meat, a huge bone-in chunk of beef in a crust of spices, cooked perfectly as ordered.

But there are disappointments, too. Maui onion rings, offered as an appetizer, look great, but they’re floury and partly soggy. One night, two chicken dishes--tandoori chicken (cooked not in a tandoor but on a mesquite grill), steeped in a pleasantly aromatic marinade, and “Ricky’s fried chicken,” in a crunchy, corn-flakey crust--were dry and almost cottony in texture, despite their other virtues. Meatloaf was homey and dull, and the accompanying mashed potatoes could have used a lot more butter. These seem more matters of detail than inherent faults. The diner gets the feeling that the kitchen is sometimes simply overwhelmed.

Desserts can be real crowd-pleasers. Who wouldn’t be seduced by a big sundae of homemade Tahitian vanilla bean and praline ice creams accompanied by little pitchers of hot fudge and butterscotch sauces and by ramekins filled with roasted almonds and silky whipped cream? But the rather curious raspberry pizza--raspberries baked atop sweetened pizza dough--was literally inedible: No one could cut through the crust.

Maybe Irving should lighten up a bit. Maybe he should hand out copies of his menu and sell postcards of the interior at the door. Maybe this would galvanize the place a bit--shake up his already very good restaurant just enough to make it even better.

The Ivy, 113 N. Robertson Blvd., Los Angeles; (310) 274-8303. Lunch and dinner served daily, late breakfast and dinner served Sunday. Full bar. Valet parking. All major credit cards accepted. Dinner for two, food only, $74 . 50-$108.50.