How to slim down your suitcase

TRAVEL-SHOP owner Judith Gilford has been giving seminars on ``How to pack for three weeks and two climates in one carry-on bag'' in the Bay Area for six years. Now she's set down her wisdom in ``The Packing Book: Secrets of the Carry-on Traveler'' (Ten Speed Press, 166 pp., $7.95).

Among the many topics covered in this resourceful book are: how to choose carry-on luggage (she shuns garment bags as too bulky, and closet space on planes is too slim); a country-by-country list of what electrical adapters you'll need; how to dewrinkle your clothes using the steam from a hotel shower (but don't try it with cotton clothes - they're too absorbent); austere checklists of items to take depending on season and trip duration; the many travel uses for plastic bags of all kinds and sizes (from carrying diaper wipes to lining suitcases); and tips for keeping children amused on the road (Walkman-type tape recorders, for one). She recommends products by name, and includes a resource list and bibliography. Her advice is travel-tested and rings true, on the whole, though it sounds overcautious at times.

Ms. Gilford's major contribution to packing seems to be ``the bundle method,'' in which clothes are laid on top of each other and then folded together around a core of toiletries and underwear. This keeps clothes compact and relatively wrinkle-free. There are illustrated, step-by-step instructions.