The notion that nothing catches a man's eye faster than a plunging neckline may be behind us. This fall the back is back, and designers from Paris to Seventh Avenue are dressing up, draping and dropping out backsides to flash a woman's lesser-seen flesh. "The bosom was fashionable in the '50s," says Dior's Marc Bohan. "Now the derriere is in the air." Observes designer Louis Feraud: "Why should we treat the back of a palace with less importance than the front?"

Why indeed. It was Christian Lacroix, the playful couturier of the House of Patou, who earlier this year caught the fancy of the high-fashion world with billowy bustles and jaunty rear-end accoutrements. Suddenly it became important to look smashing coming and going.

Most designers think that the back is an underrated female asset. "There's nothing sexier than a dress that's completely covered in the front and completely cut out in the back," says Bob Mackie. Still, there's bound to be grumbling from some men who find the change of focus, well, backward.