If Barbara Ucko's excellent dry wit could be bottled and sold, irony would not be in such lamentably short supply in the pages of American fiction. Faster than a switch-blade and just as sharp, she's a natural comic talent whose first book, "Family Trappings," is so unexpectedly and marvelously droll that my face was stiff from grinning when I finally put it down. And if this weren't enough, Ucko has created characters and situations that manage the difficult trick of seeming both real and wholly original.

First and foremost, there are Clare and Martin Fishbein, newly transplanted from Chicago to the Sun Belt and struggling to adjust. For example, when they attempt an evening stroll in their subdivision on the night they arrive in Luther -- an innocent enough pastime, they suppose -- a neighbor's dog runs out to attack Clare. And if this weren't bad enough, the owner most surprisingly proffers little sympathy:

"Y'all say you were taking a walk? Funny time to be doing it," is his maddening comment, thus firing an early round on what turns out to be a battlefield of culture shocks.

And matters are not improved by the fact that it's Clare whose new job has brought them to such a benighted spot ("one movie theater, eight gas stations, a small shopping mall, everything in danger of being overrun by creepers and vines") and an unemployed Martin who is taking care of the house.

A voice teacher and professional baritone, Martin finds his initial efforts to establish anything resembling a similar career in Luther simply too discouraging. Prospective pupils want to learn "Moon River," not lieder, and his plan to make and sell birdhouses is viewed by Clare with justifiable scorn. Only when he decides to keep busy by writing a local history does Martin perk up and have something other than ice cream runs to the Piggly Wiggly to look forward to.

Meanwhile, interlaced with the constantly entertaining narrative of the Fishbeins' evolution into upstanding citizens of the New South is the story of Lily, Clare's younger sister, and her descent into madness. This, too, has its definite comic side, although until she comes to visit Martin and Clare, one is given the merest unsettling glimpses of Lily's pathologically bizarre antics.

Then, with the two of them waiting in the heat to meet her, Lily steps off a bus, 50 pounds overweight, wearing a torn and soiled dress, with a ring in her nose and on her feet bright green "elf shoes . . . the toes decked with bells and turned up a good three inches off the ground." But what the reader has known from the beginning, Clare can't immediately accept, since, from childhood, her life has been ruled by the notion of her sister's superiority to herself.

If, in fact, there's any flaw in the sure touch Ucko displays -- deftly skewering small-town philistines with one hand, affectionately highlighting the Fishbeins' own shortcomings with the other -- it's in the portrait of Lydia Cuspin, Clare and Lily's mother. Bram Stoker and Stephen King together could hardly have invented such a monster!

"I suppose you've had tests done for Tay-Sachs and any other of those genetic diseases peculiar to those of the Hebrew faith," Lydia writes Clare upon learning of her pregnancy. "Wallace tells me Tay-Sachs is possible only if both parents are Jewish, but I say you can never be too sure . . . I still don't see why you left your job. I hope you'll manage on Martin's teaching salary he's succeeded in becoming the Luther high school's music director . If you run into difficulties, don't expect us to bail you out."

By the time, pages later, that Lydia has put in her final appearance, automatically belittling Clare and blindly singing Lily's praises, one wants to tell Ucko that she's gone too far. Lydia, who can bring even the softhearted Martin to a boil, is simply beyond "pitiful"; she's almost too awful to be true -- and that can't be said of the rest of the family trappings here, no matter how colorfully imagined.

For both Clare and Martin, warts and all, are quite perfect just as they are: a couple with a complex relationship of love and mutual exasperation that is funny and also beguiling. Ucko gives such a wonderful texture to their attachment to each other -- these two misfits who met in college when she sat in the first row and wept to hear him sing so sweetly in a nearly empty recital hall -- that one is reluctant to part with them.

"Family Trappings," in short, is a genuine discovery, and Barbara Ucko is an author from whom any lover of comic fiction will want to hear more.