HARMONY is 38 years old, soon to be 39, a showgirl at a Las Vegas casino called the Stardust. She hasn't seen her husband, Ross, for 14 years; her 16-year- old daughter, Pepper, is conducting a rebellion the latest incident in which involves a man nearly three decades her senior; her current boyfriend, Denny, has in fairly rapid succession caused her Visa card to be cancelled, wrecked her automobile, stolen a $1,300 insurance check, and run out on her; and though a few years ago she "had been said by some to have the best legs in Las Vegas and maybe the best bust too," she is now haunted by the awareness that a career founded not in talent but in beauty is rapidly fading away.

These are hard times for Harmony, in other words, but you'd hardly hardly know it from her cheerful manner. Harmony is a romantic, which "just meant you were a little more tender about things and liked to think about the good kinds of things that could happen rather than the bad kinds of things, which there were enough of, there was no point in dwelling on them." To the hardness and cruelty of the world, Harmony turns a tender cheek:

"For herself she didn't worry too much, she still loved being in the show, plus there was a lot to like about life if you could make a little effort and look on the bright side. Even a nice morning was a form of happiness, plus having a sweet guy around for a while was another form, a major form actually, major even if usually sort of brief in her experience."

To be sure, every once in a while life just gets too complicated for Harmony and she "would feel a sinking, she would start getting low and then it was like something was falling, like she couldn't keep a high heart anymore no matter how much she tried," and when those low times come she slides into some serious crying. But those downs don't last long because, as her friend Gary puts it, among her "most wonderful skills" is an "ability to see the bright side." Gary says, "I love that about you, it takes courage, you know," and he is right: in her innocent, chipper, plucky, unaffected way Harmony is as courageous a character as one could hope to meet. She thinks of herself as weak, and constantly berates herself for what she perceives as her manifold shortcomings, but in fact she is remarkably strong; she has the force of character to take life on its own terms, and the presence of mind to roll with the hard punches it deals out.

For these reasons, and for many others as well, it is quite impossible not to fall in love with Harmony while reading The Desert Rose, Larry McMurtry's ninth novel. That it is unquestionably one of his best novels may well be because McMurtry himself fell in love with her while writing it. Invariably, it seems, his most successful books have at their centers women who are strong, sexy, generous, humorous: Molly in Leaving Cheyenne, Ruth in The Last Picture Show, Aurora in Terms of Endearment, now Harmony in The Desert Rose. Certainly it is true that McMurtry is an accomplished comic writer and a satirist of considerable bite-- there is ample evidence of both gifts in The Desert Rose --but he is at his most appealing when he writes, with deep compassion and sympathy, about these tough, patient women who in every important respect outclass the men who use and occasionally abuse them:

"The sadness of men, once it got into their eyes, affected (Harmony) a lot, she sort of couldn't bear it and would usually try ad make it go away if the circumstances permitted her to, often they didn't but sometimes they did, it was mainly a desire to kiss their sadness away that had caused her to bring so many of them home. . . . Old or young, fat or thin didn't matter so much although definitely fat rather than thin if she was given a choice, she was not so drawn to the skinny guys, it was just that she sometimes got the sense that she overwhelmed them, after all she was pretty tall and had a good bust and a few of them had sort of seemed to feel that they were being smothered."

Out of the genuine goodness of her ample heart, Harmony is a pushover. Gary, a homosexual who is wardrobe manager for the Stardust floorshow, "once he even acted a little superior and told her she was like a beautiful car, a Mercedes or something, that had everything it needed except brakes." She's just a great big bundle of love; even when the sudden disappearance of her latest man leaves her heartsick, she doesn't pine for long and is ready for the next bout of happiness when it shows up --as in fact it always does. She is grateful for any little blessing, and she is sharp enough to recognize a real blessing when she sees one.

In The Desert Rose, as in all of McMurtry's most skillful work, the central figure is supported by a brilliant cast of secondary characters: Gary, her most abiding friend, "the thing that made him such a wonderful friend was that when you were really in trouble it never entered his head to criticize"; Myrtle, her neighbor, "a tiny redhead in her early sixties who had no intention of letting age or anything else get in the way of pleasure"; Pepper, her gifted but self-absorbed daughter; Mel, Pepper's 45-year-old fianc,e, whose peculiarities disguise a kind, patient and understanding temperament; Jackie Bonventre, the brassy and seemingly heartless manager of the casino floorshow who reveals himself, in an important moment, to have a more sensitive understanding of human behavior and needs than might have been expected.

These characters and others give the novel an agreeable busyness, a sense of people going about their separate and interlocking lives in just the manner that real people do. Las Vegas itself is not an aggressive presence here as it is in John Gregory Dunne's Vegas or Hunter Thompson's Fear and Loathing in Las Vegas, but a strange place the oddities of which its residents take for granted as components of their normal lives. McMurtry has chosen to narrate the story in the cool, breezy argot of the place, and the device works handsomely, making a seamless whole out of dialogue and description.

The Desert Rose is as likeable as anything McMurtry has written, but that is not intended as a wishy-washy compliment. To the contrary, it takes great skill and sensitivity to pinpoint the resilience and decency of Harmony, who in a less rounded portrait might have been a mere caricature of the dumb beauty with a heart of gold. What McMurtry finds in her is real beauty, and thereby he reminds us of what true beauty is. Perhaps that is why The Desert Rose is, in a quite unassuming way, a beautiful little book.