BOOK REVIEW : It’s Big. It’s Gaudy. It’s Simply Unbelievable. : THE LIFESTYLES OF THE RICH AND FAMOUS COOKBOOK <i> By Robin Leach (Viking Studio: $24.95; 280 pp.) </i>

Anyone who really understands the lifestyles of the famous and rich knows the first reward, always, is a great private chef. Ruth Gordon’s cook Suzanne was with her for 37 years; Elizabeth Taylor’s Bel-Air staff is so evolved that for years she even employed Princess Margaret’s former concierge to run the show.

So why does rich-and-famous connoisseur Robin Leach try to put one over on us in his new book, “The Lifestyles of the Rich and Famous Cookbook”?

Leach presenting Mrs. Larry Fortensky’s recipe for chocolate tulips feels bogus--it doesn’t play. Does anyone out there believe the industrious Joan Collins really does time in a kitchen? (Her sister Jackie Collins happens to be a great cook, but Leach hasn’t included her. Rather we get sister Joan’s rather unimaginative spaghetti Bolognese.)

Eva Gabor, the publicity hound of all time, has a superb cook in Holmby Hills, just as Gregory Peck does, also in Holmby Hills, and Johnny Carson does in Malibu. Yet here they all are, presented as if they were cooks.

So we get soap queen Jackie Zeman’s grilled fruit and Bruce Jenner’s brownies and Dame Barbara Cartland’s hard-boiled eggs with caviar. Plus Leach’s own recipe for rich and famous chicken. (He writes that he cooked his first and last steak in 1963, and “nearly burned the apartment house down.” Thus he sticks to chicken, rice and asparagus. So basic.)

The only place this book works is in the area of reality --the Beverly Hills Hotel’s salad Dionne or Monaco’s Louis XV Restaurant’s lobster bouillion. Here is where Leach could, and sometimes does, really share with us. The menus of the true chefs are superb, such as Wolfgang Puck’s various desserts and pizzas. But Leach doesn’t go far enough, or maybe he goes too far: Do we really want to know Tova Borgnine’s mother’s recipe for wedding cake? Do even the real romantics among us want to know that recipe?

If Leach would let us in on how the famous and rich really wine and dine, it would be interesting--and another book. Mrs. Gregory Peck’s place settings would be intriguing--how do you seat several movie stars at the same dinner? Or: What do movie stars do when the help is off?

Another way Leach could have gone right would be to give us not Dina Merrill’s mixed green salad, but her history . As the daughter of heiress Marjorie Meriwether Post, what was her culinary childhood like? Did the cook prepare her favorite Madeleines? Did Dina ever sneak into the vast kitchen at Mar-a-Lago in Palm Beach and make homemade fudge?

Or, instead of Princess Yasmin Khan’s fictions about the good life in Westhampton, why not have her tell us about eating on the Riviera as the privileged daughter of Aly Khan and Rita Hayworth?

This book is meant to “celebrate Leach’s 10th season” as chronicler of the stars and the climbers and the arrivistes , but it reads more like a collection of recipes from anonymous, well-paid cooks. So he takes us into the houses, but almost never when guests are there. (Diane Rozas, his co-author, has to her credit the book “Chicken Breasts.” Surely Viking Studio can do better than that for a book as expensive as this.)

Leach has traveled far since the early ‘60s when he lived in one room on New York’s 33rd Street and had no recipes, and even fewer dinner invitations. He boasts of making mental notes through the years on things such as Brooke Shields’ spring rolls and Steve Garvey’s lemon tarts.

But whom is he kidding? Is Tony Roberts’ French toast better than yours or mine? (The recipe is pretty basic.)

Finally the reader is grateful to Texas hotelier Caroline Hunt for her candor. Says the busy and rich Hunt, “I leave the cooking to those who have more time.”

So should have Robin Leach.