A corrective to the tuna salad doldrums? With its budget-stretchers (crab, lobster), hard-to-come-by ingredients (morels, nasturtium leaves), and Continental drift, this won't meet everyday needs but it could tone up the table on special occasions. Olney's recipes, frequently accompanied by reminiscent or explanatory patter, attend to flavors, temperatures, and colors--like the salad featuring concentric circles of zucchini, summer squash, and tomato wedges. Some variations are less attractive than the originals (ratatouille terrine, vitello tonnato loaf) but many recipes make full use of tomatoes, asparagus, and other seasonal favorites. The mayonnaise is always handmade (the blender variety is second best) and the desserts are always rich: ""Peaches Aswim in Rose Petals"" is the extreme. Try the asparagus quiche or marinated chicken legs with aioli for company or the several recipes that allow guests to toss their own.