Well, you know how it is: Temptation, danger, corruption, depravity -- business as usual at the romantic-novel stand. You'd think it would get boring, but Rona Randall's sure touch seems to make decadence live up to its reputation.

Nevertheless, even the exotic can become commonplace, and the permutations and combinations of passion, hatred and ambition can end up with all the allure of an article on "Twenty Thrifty Ways to Serve Truffles." This is not allowed to happen here, and the reader is grateful.

"the Mating Dance" presents a stereoscopic (that is, alternately narrated) view of half-sisters contending for the control of their actor-father's theater, and for the love of several attractive men. The legitimate daughter, the dark and and devious Clementine, is a nymphomaniac and a perfect horror, though gorgeous. She does most of the contending and is the type often included in these books to provide conflict and sensuality. Illegitimate Lucinda, one expect, will be angelically fair, compassionate and trusting. Surprise! Lucinda turns out ot be angelically fair, compassionate and trusting. She does her own thing without really understanding its undermining effect upon her sister's vilainous purposes.

This clasic dualism between good and evil extends to their artistic goals, their family relationships and their romantic entanglements. Clementine's are all selfish and calculated, Lucinda's suitably tranquil and high-minded, even in the face of considerable provocation.

Turn-of-the-century English theater provides a rich background for the struggle and is beautifully drawn from the author's own stage experience, The larger setting -- a respectable world of manners overlying unspeakable depths -- reflects the cliched view of Victorian society but certainly suits the purpose of the book, and Randall manages it all most efficiently. Her meticulous descriptions of the elaborate clothing of the era alone almost merit the price of admission.

A good deal of the action takes place in the anti-heroine's portions of the story, creating a certain imbalance every time the narrator changes. You begin to look forward to "Clementine.

One annoying detail is an inclination to hindsight in such matters as feminism, smoking, hotels named Ritz and "future firebrands," like Waston churchill. Also, the narrators occasionally deliver themselves of sage and time-proven judgments which are more irritating than not.

The plot advances almost entirely by means of various brands of sexual incident, some of it quite riveting. Now, this is knowledgeable of the author and hypnotic for the rest of us, but a niggling question arises: How in the world do books like this ever get lumped into the "romantic novel" category?

Romanticism implies sighs and hopes, artless dreams and simple fantasies fulfilled. Randall's work here is one of ugly reality in many respects. The most romantic thing in it is the conclusion that virtue can still conquer in the face of hefty opposition. Otherwise, the book aims for the prurience bone and hits it every time. Beyond the reflex stimulation at the goings-on lies an equally instinctive revulsion that is a far cry from the quintessential romantic flutter. Perhaps it is time to invent a new label for this kind of story and leave "romantic" to the novels that merit it.

"still, if vice and debauchery are your cup of tea, they're served here with sugar. For every helping of sin and depravity, you get a matching one couple the puzzling perversion of "Did she think he had merely tried to rape me?" with the guileless "I was sixteen and had endured enough of love's torment," "The Mating Dance" seems likely to please an assortment of appetites.

Not always, though, for the best of reasons.