THE CATALOG OF AMERICAN ANTIQUES, by William C. Ketchum, Jr. (Rutledge Books, $24.95). Collectors of antiques browse a lot. Most will admit that for every treasure bought hours have been spent touring shops to compare styles and prices. With this book in hand one can browse at home and get an insight on why prices vary. Stating the basic rule that "a given antique object is worth whatever a person will pay for it," the author explains in his introduction the prevailing conditions that would warrant different prices on two identical pieces. Drawing on the experiences of auctioneers, dealers and knowledgeable collectors, Ketchum gives a price range for each of the 2000-plus objects illustrated. A fully illustrated price guide is valuable, but the prices given seem somewhat optimistic. This is a handsome book, with chapters devoted - among other things - to weathervanes and whirligigs, tramp art and political memorabilia. The illustrations - 32 pages in full color - benefit from John Garetti's long experience in photographing antiques.

DICTIONARY OF THE DECORATIVE ARTS, by John Fleming and Hugh Honour (Harper & Row, $22.95). As a companion to an earlier volume, Penguin Dictionary of Architecture, the authors have written a complete reference book on furniture and furnishings of the West. From pyrex to porcelain, silk to synthetics, they have included in over 4000 entries notes on craftsmen, their wares, the factories that produced them, and the mediums used. With bibliographic notes after each entry, cross-referenced and illustrated throughout, this is an invaluable guide for the connoisseur, collector, or the just plain curious.