Sylvia Townsend Warner's stories of Elfin, which now and then appear in The New Yorker, stand forth in collected form as the accomplished and serious works of art they are. Lamely put, Warner's Elfin is a loose-knit family of very ancient Courts, invariably ruled by Queens, unobtrusively pursuing their own ways under various European hillsides in a spirit of leisurely practicality. Elfins (or fairies) are about the size of well-grown human children, tend to a jolie-laide cast of features, have wings (used only by the servant classes), and live for several centuries. They are often capable of intellectual obsessions and sometimes of romantic love, but mostly untroubled by illusions of immortality. Dealing with the inevitable, they are as sensible as turnips. It is hard to say what lovers of Tolkien's Middle-earth or White's Camelot will make of Warner's handful of Elfin kingdoms--Elfhame, Broceliande, Blokula, Schloss Dreiviertelstein, Castell Llwyn Onn. Charming names and odd bits of lore are a very small part of Warner's accomplishment. Her noncommittal tone and wry shifts of mood are not calculated to enchant hobbit-worshippers and whimsy-collectors; her exquisitely astringent prose style and musical sense of pacing are rare among modern writers of fantasy. Loss, failure, disillusionment, and prosaic compromise are the characteristic notes of these stories--but sounded with the radiance and economy of a Mozart slow movement.