Not since Emily Post published her almost classic Etiquette, has a society leader ventured to compete with her. Now comes this book, rooted in a generation of experience -- Newport, New York, Washington and foreign capitals. Commonsense and courtesy are, she says, the basis of all etiquette, with kindliness an essential, and the smoothing of social machinery an excuse. Manners are an international language. She covers the routine subjects a wide range; she strives to adapt her principles to cottage and palace, but one has suspicions that her application to servantless or maid households is done at second hand. This part alone is unconvincing. Practically every question I could evolve found an answer -- and with most of them I agreed. I think she lands to overstress class distinctions by overtipping; I think she occasionally shows a bit of the social and monied anob. But I think her market will like it.