LENA HORNE hasd had a long and not always gentle career, so it would be no surprise, if, at age 63 or thereabouts, she chose to pace herself and trade heavily on memories and residual good will. Broadway and the concert circuit have certainly proven that if a mature star wants to recapture the emotional and financial rewards of mass adulation, a decline in skills, stamina or dedication need pose no obstacle.

But that's not what "Lena Horne: The Lady and Her Music," playing at the Nederlander Theatre, is about. There's no pussy-footing around in this one-woman show, which has become Broadway's hottest ticket, and there's none of the offhand, mannered, cocktail-singing style that, for a time, was Horne's trademark. She goes all-out from curtain to curtain, and her idea of "all-out" would be impressive in a singer a third her age. To see such sustained energy and vocal and physical power alongside the craft and musicianship of someone who has been singing professionally for 45 years is nothing short of astonishing.

So, of course, is Horne's appearance. Making her entrance in a flowing white gown that clings to her bosom and sleek waist, she is the picture of elegance. But as she quickly makes clear, she isn't interested in being the picture of anything. Youthful is as youthful does. So Horne pluges right into a strutting, stomping, slinking, shouting, sweet-talking repertory of songs from her overlapping careers in the theater, movies and nightclubs -- songs like "I'm Going to Sit Right Down and Write Myself a Letter," "The Lady Is a Tramp," "Bewitched, Bothered and Bewildered," "Can't Help Lovin' Dat Man of Mine," and, of course, "Stormy Weather."

As the first half of her program nears an end, perspiration has begun collecting on her torso, and Horne mops some of it off with a handkerchief, explaining: "Sweat never hurt nobody, but it hurts the cloth. Bad, bad laundry bill." Then comes a 20-minute intermission that doesn't seem nearly long enough, and she re-emerges (with a change of costume) for another hour or so of nonstop mass seduction.

Like all good singers, Horne is a natural actress, and she possesses a sharp sense of comic timing, which she employs in the songs themselves and in between-song reminiscences of her frustrating years in the movies. Hollywood -- as she recalls with the kind of wry slant only time, prosperity and class can bring -- just didn't know what to make of a suave, sexy black singer with unusually light skin. After an audition at MGM in 1940, Horne found herself facing "six big mo-gulls" around a table, "and they says, 'You don't look like you is s'posed to look. We're going to make you a latin."

When she decided to rebuff that suggestion, the studio gave her such peripheral roles that "I can't tell you anything about the plots of the movies that I was in," she apologizes, "'cause I wasn't in any of the plots." And while she was serving as "window dressing" in the likes of "Panama Hattie," "Thousands Cheer," "Two Girls and a Sailor" and "Duchess of Idaho" -- interspersed with two memorable black musicals, "Cabin in the Sky" and "Stormy Weather" -- she had to watch Jeanne Crain, Ava Gardner and even Hedy Lamarr being cast as black women who "passed" for white.

Gardner was cast in "Show Boat" despite being a non-singer (her songs had to be dubbed), and despite the fact that Horne wanted the chance badly, as she recounts before retroactively laying out her credentials with a magnificent rendition of "Can't Help Lovin' Dat Man of Mine."

"I felt bad for a while," she says. "About 12 years."

"The Wiz" came after a long spell away from Hollywood, and Horne didn't get the part she wanted. She would rather have played the Wicked Witch than the Good Witch Glinda, she says, but when an actess is only making one movie a decade, it "don't give you much opportunity to quibble." The role came about, according to Horne, because director Sidney Lumet was her son-in-law. "The world needs more nepotism," she concludes.

But Lena Horne certainly needs no favors from anyone, and if that point hasn't been sufficiently understod in all the far corners of show business, it will be now.