BOOK REVIEW : Peak Experiences With Offbeat Genius : LOVE JUNKIE, <i> by Robert Plunket,</i> HarperCollins, $20; 256 pages

This comic novel, a tres lightweight “Madame Bovary” for our times, is like an exasperating but original friend. Just when you’ve decided to dump him or her, he or she says something that no one else could possibly have said. And you know you would really miss him or her. Or, in the case of “Love Junkie,” you know you will really finish the book, and enjoy it, despite your exasperation.

Robert Plunket’s Emma is Mimi Smithers, of Bronxville, N.Y., who is left behind by a boring husband, taken up by a cynical and witty gay friend who offers her a job at his arts funding agency, and is eventually employed by a gay porn star who turns out to be straight. Sexually straight, anyway.

Mimi speaks in what shrinks refer to as a Carmen perpetuum , or unending song, which logically springs from the language of her native Texas and her adopted Manhattan. Most of “Love Junkie” consists of Mimi’s sinuous bright ribbon of brand names, decorating and fashion opinions, astonished reactions and careless critical remarks. Figuring weight for age, Mimi is not a fount of wisdom. Plunket needs her surprise to move his book along, but this persistent posture makes her more like Candy, the heroine of a book of the same name by Terry Southern and Mason Hoffenberg, than like Emma Bovary.

Events just shower down on Mimi, as sexual experiences simply befell Candy, whereas Madame Bovary rushed out to embrace her doom. So the fact that Mimi’s husband has gone off to a little town in India called Bhopal, and he’s a chemical engineer who works for Union Carbide, or the fact that her art agency friend, Tom, looks terribly, terribly ill--these facts do not signify.

But the way Mimi and Robert Plunket put things as she floats along on her travelogue of life, redeems the whole enterprise. Mimi’s psychiatrist’s office has, disappointingly, “the sad, ill-informed air of the accessories department at Walmart. . . .” And “On TV when they interview women whose welfare checks are late, they’re all sitting on couches like these.”

There’s an inevitability about many of Mimi’s observations, which is the soul of true comedy. “Like so many other homosexual couples, they had met in the Peace Corps.” And, “Floyd, who had a tendency to confide in people, told me that they hardly ever made love anymore, except during the transit strike.”

The opportunity for Mimi to comment on gay life expands enormously when she goes to work answering mail, and eventually helping to produce a movie, for a hugely successful porn star. “It may sound odd,” Mimi opines, “when talking about a porn star, but if I had to find one word that sums up Joel’s personality it would have to be ethical . . . . He was very proud of the fact that he stood behind every pair of Jockey shorts he sold with the guarantee that they were personally worn by him.” To facilitate the mail-order side of his business, Joel always wears three pairs of Jockey shorts at once.

Though Joel turns out not to be gay (it’s hard for him to give up the pretense because he makes so much money from Slave Sheldon and others), Mimi realizes the difficulties she faces as she grows to love him. “I was no fool. I could plainly smell the proverbial coffee. He was a charismatic porn star who sold his dirty underwear. I was an upper-middle class housewife from Bronxville. He was twenty-nine. I was forty-one. He was Jewish. I was Presbyterian.”

Mimi’s love addiction (she is the junkie of the title) never is satisfied. Yes, that’s part of the definition of an addiction, but Mimi never comes close to even minor satisfaction. The resolution of the plot, if you can call it a resolution, or call it a plot, comes by way of a phone call from Ronald Reagan.

But along the way come these entrancing sentences that you could never find in any other book. “It’s rather difficult to explain,” for example, “but there is nothing quite like spying on some poor soul whose biggest thrill in life is being force-fed a can of Alpo to form a bond between you and whomever you may be doing this with.” Or “The situation sounded dreadful, and I wanted no part of it. A koala-scarred Englishwoman and an arts administrator with chronic shingles--thanks but no thanks.”

Mimi’s peak experience comes when she has to help out a sort-of friend who is servicing a man who needs more than one woman at a time to humiliate him, in order to make him feel authentically humiliated. As Mimi gamely observes when she is drafted (and here is the exception to her not being a fount of wisdom, actually):

“Being a prostitute wasn’t like I thought it was going to be. The only thing I can compare it to is waitressing. You have to stay one step ahead of the action, always planning the next thing, always anticipating, always saying those little things that make the customer feel good, like ‘What a pretty tie!’ ”

There’s a penultimate chapter in “Love Junkie” that may not approach wisdom, but certainly is on a par with Heloise of Helpful Hints fame. This chapter begins, “On the off chance you ever have a pornographic movie filmed in your home, here is a list of tips you might want to clip and save.” Mimi isn’t too bright and “Love Junkie” seems to have been tossed off by its author in a couple of rainy afternoons, but you can’t read this book without realizing Robert Plunket is some kind--some bizarre but lovable kind--of genius.

Next: Jonathan Kirsch reviews “The Buried Mirror” by Carlos Fuentes (Houghton Mifflin).