Guidebooks to Babylon.

Librarians may regard me as a highbrow pervert, frowning over their spectacles at my choice of reading matter. In certain archives, I've even been directed to sit at a solitary table, where my movements can be carefully watched. But I've learned to ignore the suspicious looks. The truth is, for any writer who is researching a ''golden age'' of vice -- whether it be Renaissance Venice, Georgian London, belle epoque Paris or fin de siecle New Orleans -- there is nothing quite so satisfying as a guide to local harlots. To the uninitiated, these clandestine directories make the most dubious of all literary subgenres. They were created, of course, to provide practical information for gentlemen travelers venturing through a city's demimonde, and so have titles that range from mildly risque (''The Pretty Women of Paris,'' ''Directory to the Seraglios'') to unashamedly coarse (''A Catalogue of Jilts, Cracks and Prostitutes, Nightwalkers, Whores, She-Friends, Kind Women and Others of the Linnen-Lifting Tribe''). The prose is rarely distinguished. Many of the guidebooks doubled as cheap erotica, filled with unsavory jokes and double-entendres. And even the most successful were designed to be disposable. Written anonymously (or with pseudonyms worthy of Bart Simpson, like A. Butt Ender or Free Loveyer), they were printed on poor-quality paper in pocket-size editions, distributed under the table and generally discarded soon after use. [ABSTRACT FROM AUTHOR]