The world of ""design""--what used to be called interior decoration--in an effete, semi-satiric, Scruples-ish sort of novel that's weak on plot, strong on dense detailings of posh accouterments (sure to bore some readers and tantalize others). Horn's heroine is rich, beautiful trend-setter Eleanor Odell, who has just broken up with doctor-husband Herb (a lousy lover who couldn't care less about dÃ‰cor) and is about to plunge into the decoration of her new Fifth Avenue co-op. Her choice of designer: gorgeous, bisexual Stephen Petronio, hot new genius of the sensual, fantastical, free-associative look but (unbeknownst to Eleanor and everybody else) really just a workmanlike type who's been stealing his ideas from designers of the past. So, though Eleanor and Stephen are soon collaborating on her $500,000 interiors, it's actually Eleanor (a frustrated, half-trained designer herself) who's supplying the bright ideas. And Stephen resolves to make Eleanor his permanent partner by having her fall in love with him--an easy job, especially once he introduces her to such joys as oral sex avec lemonade. Things get fraught, however, when this trendy new team is hired by Claire Gillis, tasteless but super-powerful ""Queen of the Interior Desecrators,"" to do the nine-million-dollar design for a luxury hotel in Gambia: Eleanor's superior talent keeps surfacing embarrassingly; Claire (with the flimsiest motivation) sets out to destroy Eleanor; Stephen's Fire Island lover, who has learned his secret, blackmails him into steady stud service. And the truth eventually comes out in New York magazine: Eleanor wins respect as a solo designer. . . while Stephen finds calm with a new lover and the start of an honest career. What little plot there is here disintegrates about halfway through; and none of the characters has as much reality as his or her scrupulously described outfits (Stephen attends a major do in ""white chenille top, black pegged cotton trousers, and black Adidas sneakers, with his hair slicked back with coconut oil""). But some of the bitchy repartee snaps nicely; Horn is undeniably au courant with his Manhattan-chic reference points (the lovers' ""song"" is a piece by Philip Glass!); and there'll always be an audience for paragraph after paragraph of minutely described furniture, eatables, parties, and other brand-name, jet-set phenomena.