Empathetic look at French writer Loti, Pierre Loti - the Legendary Romantic, by Lesley Blanch. San Diego: Harcourt Brace Jovanovich. 336 pp. 15.95.

Pierre Loti was the most flamboyant French writer of the late 19th century. As Julien Viaud - his real name - he was a competent career naval officer. Who was the real man under the luxuriant black mustache? Hometown neighbors described him as the dutiful son of a large Huguenot family. Some saw him as a sort of Victorian-era voyeur, viewing the pagan's life in Tahiti; others, as secret lover in rakish Turkish fez, wooing a forbidden harem girl. Actually, he was all of these.

Naval duty offered Loti the opportunity to visit exotic ports, but it was Loti's own curiosity that sent him exploring native haunts and habits from the kasbah to Indochina. As a result, Loti's rich imagination spun his real-life adventures into thinly veiled autobiographical novels and travel books, admired by fans around the world.

Loti's ''reekingly sentimental'' (as the author calls them) works may deserve to be forgotten in a century of different reading tastes, but eccentric Loti himself does not. With empathy, Britisher Lesley Blanch recreates the gentle, lonely figure, who felt more secure in daydreams than reality, the childlike ''man of contradictions'' who found more pleasre in Islamic Turkey than in his native France.