What lamentations enchant the wind""--this from an Arab song Isabelle Eberhardt transcribed; what dissonances hover over the short, nomadic life of this exaltee only to end in ""disorder and constant disappointment."" Born in 1877, Isabelle (who surfaced briefly in Lesley Blanch's The Wilder Shores of Love--not acknowledged here as one of the bona fide sources) was the fifth child of a woman of means and her lover, a lapsed Pope of the Russian Orthodox Church. They emigrated with her legitimate children to Geneva where this neurasthenic family (two would commit suicide) were confined in their home Villeneuve by the stonyhearted ex-Pope, ""Vava."" A half-brother, with whom Isabelle shared conspiratorial hopes and a dream of the East, left for the Foreign Legion. Isabelle, in the men's clothes Vava dressed her in for security, later escaped to Algiers where she appeared in a burnoose and fez, beginning the years of drifting back and forth from the Continent, across the Sahara, and toward some dual ideal of freedom and mystic identification. She was accepted by a special Moslem tribe, confident that she would become one of their secret saints; always of uncertain status, she was at one point attacked, notoriously tried, and expelled from Algeria (but retained her access by marrying a very dependent Spahi soldier); she sketched, lectured, and kept many diaries, used here along with recently retrieved materials. She kept disappearing into lonely reaches, drank and smoked kif increasingly, became as depressive as others of her unhappy family, and, at 27, returned to ""the great, eternal sleep of the grave"" having died in a flash flood. . . . What a splendid curiosity, this ardent, ambitious, failed romantic--a frail shade of T. E. Lawrence. Cecily Mackworth, an experienced writer, has retraced her steps both in fact and in word with tasteful and finely attuned sympathy.