BOOKS WE LOVE : One More Italian Cookbook You’ve Got to Have : TRATTORIA COOKING, <i> By Biba Caggiano</i> . <i> (Macmillan: $25; 346 pp.) </i>

Why Italy? That’s the question a lot of us have been asking for the last several years. Why has every corner restaurant become a trattoria? Why have pizza and pasta become as much a part of our modern diet as hamburgers? Why have French restaurants suddenly become as scarce as, well, denti di galline ?

Most important, why on earth would you want another Italian cookbook? After Bugialli and Boni, Hazan and Field, is there anything left that really needs to be said?

And then along comes one more Italian cookbook that answers all of those questions quite nicely.

It may be a while before “Trattoria Cooking” gets out of my kitchen. The appeal of Italian cooking is its straightforwardness, the way it embraces and celebrates the essential nature of the ingredients without trying to manipulate them into something else.

Though it is foolish to claim that you can’t eat a bad meal in Italy, what is truly remarkable is how frequently you can pop into some little place in the middle of a walk and eat wonderful food.

And that’s what Caggiano--chef and proprietress of a highly praised Sacramento trattoria of her own--has done. What she brought back are dishes such as: Pork Spareribs With Spicy Beans, string beans with anchovies and garlic, Buridda (baked assorted fish, tomatoes and onions) or penne with radicchio and pancetta .

Simple tastes, big flavors, good cooking.

COSTINE DI MAIALE IN PADELLA CON FAGIOLI PICCANTI (Pork Spareribs With Spicy Beans) 1/2 cup dried white cannellini beans, picked over and soaked overnight in plenty of cold water 1/3 cup olive oil 8 pork spareribs, cut into single ribs (about 2 1/2 to 3 pounds) 1 medium onion, finely minced 2 cups dry white wine 1/4 cup red wine vinegar 1/2 teaspoon crushed hot red pepper Salt

Discard any beans that come to surface of water. Drain and rinse beans under cold running water. Place in medium saucepan and cover with cold water. Bring to boil over medium heat. Reduce heat to medium-low and cook beans little more than halfway, 35 to 40 minutes. (Beans should be tender but still quite firm because they will continue cooking with spareribs.) Drain beans and place in bowl until ready to use.

Heat olive oil in large skillet over medium-high heat. Add as many ribs as can fit into skillet without crowding. Cook until ribs are golden brown on both sides, 7 to 8 minutes, then transfer to plate and brown remaining ones. Discard half of fat.

Add onion to skillet and cook, stirring few times, until lightly golden, 2 to 3 minutes. Add wine, vinegar, crushed pepper and season to taste with salt. Bring liquid to fast boil, then reduce heat to medium-low. Return ribs to skillet, add beans and mix well. Cover skillet and cook until meat is tender and begins to fall away from bone, 45 minutes to 1 hour. Stir few times during cooking and add bit of broth or water, if liquid in pan reduces too quickly. At end of cooking time, there should be about 1/2 cup of pan juices left in skillet. Serve hot. Makes 4 servings.

Each serving contains about: 705 calories; 190 mg sodium; 103 mg cholesterol; 49 grams fat; 19 grams carbohydrates; 29 grams protein; 1.67 grams fiber.

In this preparation from Biba Caggiano’s “Trattoria Cooking,” the onions are cooked in olive oil until tender and stirred quickly with a bit of garlic and anchovy. The onions are then spread in the bottom of a baking dish and layered with slices of tomatoes, assorted fish, more onions and tomatoes and then baked. “This wonderful dish looks good, tastes even better, and can be assembled several hours ahead and baked at the last moment,” she says.

BURIDDA (Baked Assorted Fish, Tomatoes and Onions--Genova Style) 1/3 cup olive oil 2 large onions, thinly sliced 3 anchovy fillets, finely chopped 3 cloves garlic, finely minced 2 pounds ripe, juicy, pear-shaped tomatoes, cut into 1/4-inch rounds Salt Freshly ground pepper 1 pound firm-fleshed fish, such as sea bass, halibut, or mahi-mahi, cut into 4 serving pieces 3/4-inch thick 1/4 pound sea scallops 1/4 pound medium shrimp, peeled and deveined 2 tablespoons chopped parsley

Heat 1/4 cup olive oil in large skillet over medium heat. Add onions and saute until onions begin to brown, 5 to 6 minutes. Add anchovies and garlic and cook, stirring, about 1 minute.

Spread half onions in bottom of baking dish, top with half tomatoes and season lightly to taste with salt and pepper.

Arrange fish and shellfish over tomatoes and top with remaining onions, spreading evenly over fish. Cover with remaining tomatoes. Season lightly to taste with salt and pepper. Sprinkle with parsley.

Pour remaining oil over tomatoes and bake at 350 degrees 25 to 30 minutes. Let dish stand few minutes. With large spoon, remove some of excess oil and watery juices from pan and serve. Makes 4 to 6 servings.

Each serving contains about: 402 calories; 373 mg sodium; 146 mg cholesterol; 22 grams fat; 17 grams carbohydrates; 34 grams protein; 1.84 grams fiber.