No Truth Before Its Time : VENUS ENVY: By Rita Mae Brown : (Bantam Books: $21.95; 320 pp.)

What Rita Mae Brown does best is create irreverent individualists, usually lesbians, who thumb their noses, always attractive, at society and then have a great time watching everybody squirm. We readers enjoy it as well, especially when Brown doesn’t take herself too seriously in the attempt to be profound.

Molly Bolt, the hero of her first novel, “Rubyfruit Jungle” (1973), is a dashing iconoclast who is one of the first characters in literature to break the lesbian-as-misfit stereotype. Hortensia Banastre, from “Southern Discomfort” (1982), is a rich white woman in 1918 Montgomery who has a passionate love affair with a 15-year-old black boxer named Hercules Jinks. In all, there have been 14 books over the last 20 years--mysteries, novels and even a how-to book about writing. A prodigious output no matter how erratically crafted some of the work is.

Now we meet 35-year-old Mary Frazier Armstrong in Brown’s new novel “Venus Envy.” (Don’t groan. Somebody had to do it.) Frazier, as Mary is known to her friends, is cut from the same cloth as Molly and Hortensia, except that it takes a botched cancer diagnosis to drag her out of the stifling upper-class closet she’s grown accustomed to.

As the book opens, the terminally ill hero is sitting in her Porthault-sheeted hospital bed, counting her blessings (“No more mortgage payments and no more vile temptation as the doors of Tiffany’s yawn at me like the very gate of Hell”) and her regrets (“She had never truly loved anyone”).

She has also never told most of the people in her life that she is a lesbian. This she decides to do, by letter, right before she finds out that--whoops!--she’s not dying at all. She’s only got a nasty case of misdiagnosed bronchitis. But the letters have already been mailed, and the best part of the novel is about to begin.

It’s the best part because it’s here that Brown allows her characters some slack to live their own lives. Where the hospital scenes were full of contrived blessings or parting shots from family and friends, now we get to read the letters, see and hear the cataclysmic reactions of Libby, Frazier’s cold, controlling mom; Billy, her closeted and shallow gay escort/friend; Ann, her closeted, overly needy lover, and Carter, her priapic, alcoholic brother.

Almost everybody is threatened by the news, either because they’re afraid they’ve been “outed” by association or because being a lesbian just isn’t acceptable in the Charlotte, N.C., country-club set.

Yet Frazier, who luckily makes gobs of money as a successful art dealer, not only survives but thrives as she risks, finally, being herself. Which still leaves one problem--someone to love. Brown solves this through a gratuitous device: Frazier is jolted with electricity while changing a faulty light fixture near her favorite painting, an anonymous 17th-Century depiction of Mount Olympus. She conks out and into the arms of the beautiful and bisexual Venus, who is suddenly very much alive. Deus ex machina, literally.

“Drawn into the body of Venus, a womb of fire cleansed her. . . . A strong hand slipped under her head and cool nectar was poured down her throat. Venus wiped her lips. ‘I’m sorry. I forgot you’re human.’ ”

Much of this last section of the book on Olympus is funny and shrewd and charming. It’s a kick to see Mercury flipping channels on his big-screen TV and listening to his Bang and Olufsen audio system. It’s not so much fun to listen to Venus tell Frazier what to do next.

“It doesn’t matter that not everyone will accept you for yourself. . . . Go back and work and reach out to the people who truly love you and reach out to new people. Hold your head up. You’re as good as anybody. And you told the truth as best you know. That in itself is a miracle.”

This idea, which has been stated several times by different characters, points to the main problem with this often witty and tender novel. Rita Mae Brown is pulling too many strings. She lets much of her dialogue get didactic; she telegraphs conflicts and character’s dynamics; she gives us long labored passages of Frazier’s thoughts to make her point. Brown needs to relax and stop worrying that we won’t get the message. We will.