With its multiple appeals--to gourmets, dieters, and kitchen-speed freaks--this may find a hearty following. The recipes call for more interesting substitutions than Truax' The Woman's Day Book of Thin Italian Cooking (p. 686), are simpler and more reliant on a few flavors--white wine, lemon, and dill, for example, on fish. For vitello tonnato, smaller amounts of vegetable oil, white wine, and ricotta substitute for the olive oil and mayonnaise of the original. Like other noodle-pushers, Celli insists pasta is possible--as a small course, not a side dish, and without creamy accompaniment. Calorie counts are indicated--a mere 140 for sole limone--and cooking times are estimated. Mangia.