Aaah. A day at the beach and a book. But as you daydream between paragraphs, it's not about how you would escape the double agent's dilemma, nor the fiery speech you would make to the heroine's two-timing lover.

In this chapter, halibut steaks are marinated overnight in a spicy yogurt sauce spiked with fresh ginger root, lime and coriander. In your fantasy, the fish is grilled over hot coals until the surface is crusty and the meat is moist and velvety within. The recipe suggests fresh tomatoes as an accompaniment; you will pick up some beefsteaks at the local farmer's market, then buy strawberries -- no, blueberries -- and blend them into an icy sorbet . . .

Particularly if you're going to spend the day just sitting on the beach, light summer reading better mean light summer eating, too.

A couple of years ago, when government findings on the health benefits of a low-everything diet starting being interpreted by cookbook authors, there were few books that combined sound nutritional advice with innovative recipes. Either the advice was good and the recipes weren't, or vice versa. (Not that that still doesn't occur. "The Setpoint Diet," a highly rated book Ballantine, $3.50 written by Dr. Gilbert A. Leveille, has a recipe section filled with convenience ingredients such as instant pudding, frozen whipped topping and cake mixes.)

Now, while the bookshelves and bestseller lists are still packed with books of dubious nutritional merit (see today's Health Section), there is a growing handful of cookbooks in which reputable medical doctors, chefs, caterers or dietitians have collaborated to produce some interesting eating. And if you know what to look for, there are several all-purpose cookbooks that contain recipes suitable for light eating, too.

* The emphasis in these better cookbooks isn't the deprivation diet food of yesteryear. It's food that you will really want to eat.

"In the past, 'good food' and 'food that is good for you' were often seen as mutually exclusive: Food could be one or the other but never appeared to be both. And yet there is no valid reason why there should be any contradiction between eating well and eating healthfully," writes Anton Mosimann, chef of London's Dorchester Hotel, and author of the brand new "Cuisine Naturelle" (Atheneum, $29.95).

Cold Vegetable Soup with Basil, Grilled Monkfish Tails with Fresh Herbs, Terrine of Oranges with Raspberry Sauce -- these are a few of Mosimann's recipes that rely on neither oil, butter, cream or alcohol nor excessive salt or sugar, instead they depend on simple preparation and the freshest ingredients.

But you don't have to cook like a Guide Michelin two-star chef all the time to eat lightly -- and well. "Jane Brody's Good Food Book," by Jane Brody (W.W. Norton and Co., $22.95) contains a wealth of recipes for everyday eating as does "The New American Diet," by Sonja L. Connor, M.S., R.D. and William E. Connor, M.D. (Simon and Schuster, $18.95.), the book that contains your fantasy halibut.

Thus, here are some preparation tips and recipes from some of this summer's best light reading:

RECIPE MARINATED BAY SCALLOPS WITH CILANTRO AND YELLOW PEPPER PUREE (4 servings) 6 ounces bay scallops

1/2 cup fresh lemon juice

2 jalapen o peppers, halved

* FOR THE PEPPER PUREE:

* 2 medium yellow or red bell peppers, cored and seeded

1/2 small onion

1 small clove garlic, crushed

1 small piece fresh or dried hot pepper

1 1/2 teaspoons walnut oil

1 1/2 teaspoons red wine vinegar

1 1/2 teaspoons fresh lemon juice

* FOR SERVING:

* 3 tablespoons lime juice

Freshly ground black pepper

1/4 cup chopped cilantro

Pull off and discard the tough muscles on each scallop, then place the scallops in a bowl with the lemon juice and jalapen o peppers. Refrigerate overnight.

To make the pepper pure'e, roughly chop the bell peppers and onion. Place them in a heavy pot with the rest of the pure'e ingredients. Bring to a boil, cover, and lower the heat so the mixture simmers. Cook for 30 minutes. The mixture should be very soft. Uncover and let it cool to room temperature. Put the cooled mixture into a food processor or blender and pure'e until smooth.

To serve, drain the scallops. Divide them among 4 coquille shells or other small serving dishes. Add the lime juice to the yellow pepper pure'e and spoon it over the scallops. Grind black pepper on top and sprinkle with the cilantro.

Calories per serving: 81. Protein: 7.4 grams. Cholesterol: 13.4 milligrams. Fat: 2.4 grams. Saturated fat: 0.2 grams. agcrdt3 From "The Four Seasons Spa Cuisine," by Seppi Renggli (Simon and Schuster, $17.95) RECIPE SZECHUAN NOODLES WITH PEANUT SAUCE (6 servings)

12 ounces spaghetti, linguine or similar pasta

* FOR THE SAUCE:

* 1/3 cup hot water

1/3 cup smooth peanut butter (preferably all-natural)

2 teaspoons reduced-sodium soy sauce

2 teaspoons vinegar (preferably white wine or rice)

2 scallions, finely chopped, divided

2 cloves garlic, very finely minced

1 teaspoon sugar

1/4 teaspoon hot red pepper flakes, or more, to taste

* Cook the pasta in boiling water until it is al dente. Drain the pasta, set it aside, and keep it warm.

Meanwhile, in a medium bowl, blend the water and peanut butter. Stir in the soy sauce, vinegar, all but 1 tablespoon of the scallions, garlic, sugar and hot pepper flakes.

Combine the sauce with the hot spaghetti in a serving bowl. Garnish the dish with the 1 tablespoon of reserved scallions. Serve either hot or at room temperature.

Calories per serving: 306.

agcrdt3 From "Jane Brody's Good Food Book," by Jane Brody (W.W. Norton, $22.95) RECIPE MEXICAN CHICKEN SALAD (8 servings)

1 medium head lettuce (about 12 ounces), washed and dried

2 scallions, chopped

15-ounce can kidney beans, drained

1/2 cup chopped green bell pepper

1 cup cooked chicken, chopped

* FOR THE DRESSING:

* 3 tablespoons chicken broth

2 tablespoons safflower or corn oil

2 tablespoons red wine vinegar

1 tablespoon fresh lime juice

1 clove garlic, minced

1 1/2 teaspoons sugar

3/4 teaspoon chili powder

1/2 teaspoon salt

1/3 cup chopped fresh cilantro

Shred lettuce and place in a salad bowl. Add scallions, beans, bell pepper and chicken.

Make dressing by mixing dressing ingredients together in a blender. Just before serving, lightly toss dressing with chicken salad ingredients. Serve.

Calories per serving: 138. Fat: 4.5 grams. Percentage of calories from fat: 29.

From "Food for Life: The Cancer Prevention Cookbook," Dr. Richard Bohannon, Terri P. Wuerthner and Kathy Klett Weinstock (Contemporary, $17.95) RECIPE SUMMER FRUIT IN SPARKLING CIDER (8 servings) 2 cups cubed fresh pineapple

2 cups sliced nectarines

1 1/2 cups pitted fresh cherries

1 1/2 cups seedless green grapes

1 cup sliced plums

2 cups sparkling apple cider, chilled

* Combine fruit in a large glass bowl, and freeze 30 minutes or until partially frozen. To serve, pour cider over fruit, and serve immediately.

Calories per serving: 116 calories. Protein: 1 gram. Fat: 0.6 grams. Carbohydrates: 29 grams. Cholesterol: 0. Sodium: 4 grams.

From "Cooking Light '86" (Oxmoor House, $19.95) RECIPE MARINATED RED AND GREEN CABBAGE (8 servings)

3 1/2 cups shredded red cabbage (about 1 pound)

3 1/2 cups shredded green cabbage (about 1 pound)

2 large carrots, grated

1 large red onion, very thinly sliced

2 tablespoons finely chopped fresh ginger

1 cup cider vinegar

1/2 cup golden raisins

3 tablespoons honey

2 tablespoons safflower oil

1/2 teaspoon salt

3 scallions, trimmed and sliced

Freshly ground black pepper

*Pour enough water into a large pot to fill it about 1 inch deep. Place a vegetable steamer in the pot and bring the water to a boil. Put the cabbage and carrots in the steamer, cover the pot tightly, and steam the vegetables, stirring them once, for 5 minutes. Drain the vegetables well and transfer them to a mixing bowl. Add the onion, ginger and vinegar, and toss. Set the vegetables aside to marinate for at least 4 hours.

Squeeze the marinated vegetables a handful at a time over a saucepan to catch the juices; as you work, transfer the drained vegetables to a bowl. Boil the liquid over high heat until it is reduced to 1/2 cup -- about 5 minutes. Add the raisins and remove the pan from the heat. When the liquid has cooled, whisk in the honey, oil and salt. Pour the sauce over the drained vegetables and stir in the scallions and pepper. Serve chilled or at room temperature.

Calories per serving: 121. Protein: 2 grams. Cholesterol: 0 mg. Total fat: 4 grams. Saturated fat: 0 grams. Sodium: 156 mg.

From "Fresh Ways With Vegetables," by the Editors of Time-Life Books (Time-Life Books, $16.95) RECIPE GRILLED FILLET OF TURBOT WITH CRAB (4 servings)

4 fillets of turbot or halibut, about 5 ounces each, skinned

Salt and freshly ground black pepper

3 tablespoons finely chopped shallots

2 tablespoons fresh whole-wheat bread crumbs

2 ounces crab meat

2 teaspoons fresh chopped dill

Fish stock or water

2 medium zucchini, finely diced

3 tomatoes, seeded and diced

* Season the fillets of turbot with salt and pepper, then grill for 2 minutes on each side. Saute' the shallots in a nonstick pan, stirring, until transparent. Add the bread crumbs, crab meat and dill and moisten with a little fish stock or water. Place this mixture on top of the turbot fillets and grill for about 5 minutes longer until the mixture is golden brown.

Blanch the zucchini in boiling salted water, drain and mix with the tomato dice. Arrange the fish on 4 individual plates and serve with the vegetables.

Calories per serving: 270.

From "Cuisine Naturelle," by Anton Mosimann (Atheneum, $29.95) RECIPE COLD SMOKED SALMON OMELETTE (2 servings)

2 whole eggs

2 egg whites

Pinch cream of tartar

1/8 teaspoon salt

Pinch pepper

2 ounces feta or 1 1/2 ounces che vre

3 1/2 ounces smoked salmon

1/2 cup packed watercress, leaves and tender shoots only

* Put whole eggs and whites together in a bowl with cream of tartar. Heat a nonstick skillet for 2 minutes over medium heat. Beat eggs with a whisk until light and frothy. Pour into pan, reduce heat as low as possible, cover, and let rest 3 minutes or until eggs are set. Season with salt and pepper. Remove from pan and allow to cool for about 3 minutes.

Crumble cheese over surface, cover with salmon and watercress. Gently slide omelette onto a piece of plastic wrap. Using plastic wrap to help lift the eggs, roll the omelette as tight as possible, twist the ends, and tuck the ends under the roll. Chill. Remove from refrigerator, slice into 1-inch slices, and garnish with additional watercress. May be prepared one day in advance. It travels well and should be served at room temperature.

Calories per serving: 255.

From "The Snowbird Diet," by Donald S. Robertson, M.D. and Carol P. Robertson (Warner, $8.95) RECIPE ICY OLIVE SOUP (8 servings) An unusual cold soup, great on hot summer evenings.

2 cups plain lowfat yogurt

2 10 3/4-ounce cans chicken broth

1 cup sliced black olives

1/2 cup chopped scallions

1/2 cup chopped green bell pepper

1 cup chopped cucumber (bite-size pieces)

* Stir yogurt until smooth. Add chicken broth and stir until blended. Add remaining ingredients and stir to distribute vegetables. Cover and refrigerate for 4 hours.

Calories per serving: 145.

From "The New American Diet," by Sonja L. Connor, M.S., R.D. and William E. Connor, M.D. (Simon and Schuster, $18.95)