Zepp, a home economist who develops new products for a food company, offers a highly readable beginner's guide to microwave cookery, with bold-faced listings of ingredients that stand out clearly from brief, lucid directions. Novices will find reasonable explanations for a variety of functionsfrom defrosting a frozen cake to selecting equipment. Unfortunately, much of the standard repertoiresausage-macaroni skillet, creamed dried beef, meatballs and tomato sauce, jiffy tuna casserolewill interest only the most timid of cooks. Also, considering that the oven itself is a timesaver, there is a disappointing reliance on convenience foods, as in the green-bean bake, ham-and-cheese casserole, fast-and-fluffy orange pie and pina-colada cake. However, a few dishes, such as crab quiche or individual salmon loaves, demonstrate that microwaved food can be interesting. 50,000 ad/promo; author tour. Illustrations. (May)