A LIVING ghost walks on Broadway. Colorless and thin to the point of transparency, it is far scarier than the make-believe ghouls — the vampires and phantoms in opera cloaks — who sometimes occupy the stages around Times Square. Though its guises are many, it always exudes the same damp aura of unconvincing jollity, like that of a superannuated party girl who lost her confidence with her youth and has taken to wearing her daughter’s trendy clothes. Such is the face of the American musical in the year 2006.

The dispiriting quality of last Tuesday’s nominations for the Tony award — including double-digit nods for “The Drowsy Chaperone” and “The Color Purple” — are hardly cause for celebration. True, bulletins on the musical’s failing health have been posted with weary regularity since at least the 1960’s. But in the Broadway season that just ended officially, this once lively art seemed finally to have crossed the border that divides flesh from ectoplasm.

A dozen “new” (and the word insists on quotation marks) musicals opened on Broadway during the last year. Yet no matter how loud their scores or colorful their costumes, few of these productions had robust existences of their own. Often inspired by movies (“The Wedding Singer,” “Tarzan”), pop songbooks (“Lennon,” “Ring of Fire”) or best-selling novels (“Lestat,” “The Color Purple”), they are to their source material what the T-shirts and souvenir programs on sale in theater lobbies are to the shows within: disposable reminders of the real things.

The Broadway musical as an artificial aide-mémoire, a phenomenon that lets audiences experience the deeply familiar in newly diluted forms, has been incubating for more than a decade. And I’m not talking about revivals, which are traditionally what people are complaining about when they say there is nothing new under the neon.

There were only two notable musical revivals this season (well, three if you count the misfired deconstruction of “The Threepenny Opera.”), and they were informed by such imagination and insight that they qualify more as reinventions than pro forma revivals: the British director John Doyle’s “Sweeney Todd,” which turned the Stephen Sondheim classic into a claustrophobic journey into madness, and Kathleen Marshall’s buoyant staging of “The Pajama Game,” which found a rebellious rock ‘n’ roll spirit in a show remembered as a square slice of 1950’s Americana.

These productions, which are rare in their lack of interpretive laziness, are too vibrant, too aggressively present tense to be dismissed as nostalgia. Cultural nostalgia is about comfort, not confrontation, and encourages consumers to relive an illusory time when things seemed simpler, lighter, more fun. The extraordinary element about the current crop of new musicals is they don’t even really try to summon other worlds or eras or fantasy lands; what they do is point, with a huckster’s wink and a host of bright shorthand references, to best sellers, hit movies and Top 40 songs that market surveys guarantee audiences already know and love.

What is being sold isn’t so much the comfort of nostalgia as the reassurance of brand names. It can only be a matter of time before “Ronald McDonald: The Musical” comes to town.

In this season alone we had musicals with scores composed entirely of songs famously recorded by the eight-track funk group Earth, Wind and Fire (“Hot Feet”), the Four Seasons (“Jersey Boys”), John Lennon (“Lennon”) and Johnny Cash (“Ring of Fire”).

Both “Lennon” (a feel-good hagiography of its troubled title character) and “Ring of Fire” (which presented songs associated with Cash in a sort of everyman cycle of life) seemed determined to strip their subjects of the ache, anger and energy that made them stars in the first place.

Enacted by the kind of clean-cut, blandly interchangeable performers found in revues in theme park pavilions, “Lennon” and “Ring of Fire” transformed their outlaw heroes into music-box teddy bears. Children of parents who grew up in the 1960’s, who had danced with their adolescent demons to the music of Cash and Lennon, wouldn’t have a clue from these sanitized shows as to why such music might once have seemed threatening and exciting. (The same process of neutering occurred the previous season with “All Shook Up,” a comic-book take on the age of Elvis.) You would have to catch Harry Connick Jr., making his Broadway debut as the leading man in “The Pajama Game,” channeling the sexual challenge of the young Presley and Sinatra, to feel the musical heat of an earlier generation of youth.

The turning of movies into musicals, now a well-established fact of commercial life on Broadway, has given birth to enough winners (“The Lion King,” “The Producers,” “Hairspray”) that the process can’t be dismissed out of hand. But the ways in which the trend has been manifested this season are grim. The latest self-cannibalizing Disney musical, “Tarzan,” adapted from the company’s 1999 animated feature, feels like a protracted stunt to promote sales of the cartoon DVD, despite all the time and many millions that have obviously been sunk into the show.

The plot isn’t always comprehensible to people who haven’t seen the film. The musical, directed by Bob Crowley, passes in a green haze of performers dressed up in jungle flora and fauna, swinging in harness above the stage and the audience, plus a blur of Phil Collins songs performed, with lots of synthetic smoothing and enhancement, by the kind of anonymous cast that populates “Ring of Fire” and “Lennon.” I found the music bearable only (heaven help me) if I translated it back into the voice of Mr. Collins in my head, because then I could recall what charmed me about the original movie.

Cultists of Anne Rice’s series of novels about existentially challenged vampires must feel similarly frustrated when watching “Lestat,” the first Broadway offering from another entertainment conglomerate, Warner Brothers, which produced the film version of Ms. Rice’s “Interview With the Vampire.” With a book by Linda Woolverton and songs by Elton John and Bernie Taupin, “Lestat” turns Ms. Rice’s unhappy undead into a group suggesting a bunch of whiny “American Idol” contestants in Regency romance costumes. (My nephew, a fan of the books, growled at intermission: “This is so wrong. These people are supposed to be beautiful.”)

Like that of Mr. Collins, Sir Elton’s score feels as if it were little more than shiny aural wallpaper. If you listen closely (which requires serious focus), you can perhaps discern vestiges of earlier Elton John hit songs you once enjoyed.

“The Color Purple” — based, the program specifies, on both Alice Walker’s novel and the Steven Spielberg film it inspired — is certainly a more honorable endeavor, a status acknowledged by the 11 Tony nominations. Its cast is filled with performers of distinctive and engaging talent, including LaChanze in the role played by Whoopi Goldberg on the screen. But as directed by Gary Griffin, with a book by Marsha Norman, the musical is so intent on touching on every plot point in the novel that the show starts to feel like a singing set of Cliffs Notes made for speed reading.

This musical does have the virtue of making you want to go back to the book, since there seem to be some provocative ideas and characters kicking around on the stage. As one of the show’s producers (and its most essential sales rep) is Oprah Winfrey, she of the mighty book club, this redirection feels oddly appropriate.

In like manner “The Wedding Singer” may steer you back toward the movie it is based on, to savor the oddball romantic chemistry of Adam Sandler and Drew Barrymore. The show itself — adapted from a movie from the long-ago 1990’s about the long-ago 1980’s — is a scrapbook of verbal and visual quotations from the age of MTV, so doggedly superficial that it makes “Grease” look like “La Bohème.”

And speaking of the 1980’s, the composer who ruled the West End and Broadway in that era, Andrew Lloyd Webber, returned with the short-lived “Woman in White,” a pallid, freeze-dried version of the Victorian novel by Wilkie Collins that quaintly echoed the time when poperetta was king and almost made me sentimental about “The Phantom of the Opera” and “Cats.” (Life was beautiful then.)

One new production had the smart idea of directly addressing the irritation factor in the prevailing musical fare. “The Drowsy Chaperone” — which originated at the Toronto Fringe Festival and opened in New York, like a graffiti exclamation point, toward the end of a burned-out season — begins with a voice in the dark, offering up a prayer that doubtless reflects the thoughts of many a contemporary theatergoer. “Dear God, please let it be a good show,” says the voice, which proceeds to itemize what constitutes one: brevity, color, sparkling music and glamour, a world you can escape into.

The voice belongs to a character called Man in Chair (played with winning anxiety by Bob Martin), who turns out to be a member of that rare but indomitable species, the theater queen, who has a memory of musicals past as long as Broadway itself. Alone in his bleak urban apartment, this fellow puts on a cast album of a larky show from the late 1920’s, “The Drowsy Chaperone,” and, lo and behold, it comes to life before his eyes.

The problem is that the show-within-the-show isn’t nearly as entertaining as what the Man has to say about it.

Like much else on Broadway, it has the twice-removed feeling of a pastiche of a pastiche, in this case recalling 1950’s and 60’s sendups of Jazz Age frolics (“The Boyfriend,” “Dames at Sea”). What gives “The Drowsy Chaperone” its tasty authenticity is the visceral love of the musical form as embodied by the excellent Mr. Martin. And while most of the hard-working cast doesn’t quite justify such love, Sutton Foster’s portrayal of a rising 1920’s stage star is infused with both skill and audacious enjoyment of what she’s doing. She understands what she is parodying, which is crucial. But just as important, the passion behind the performance makes us understand why Mr. Martin’s character swoons over musicals.

That this kind of portraiture continues to occur, however sporadically, in musicals in New York is what keeps all show queens hopeful, against the odds. The real thrill of the smash hit “Jersey Boys” lies not in the mimetic rendering of old Four Seasons songs, but in the sheen of conviction exuded by John Lloyd Young, the young actor playing Frankie Valli. His performance turns what might have been karaoke imitation numbers into personal cris de coeur, and it rips through the synthetic fabric of a by-the-numbers biomusical.

The same exciting feeling of emotional truth coursed through Christine Ebersole’s performance in “Grey Gardens,” an Off Broadway show that qualifies, by default, as the most original new musical of the season. (It is scheduled to reopen on Broadway in the fall.) Yes, it too was adapted from a movie — in this case, the notorious 1975 documentary by the Maysles brothers about a mother and daughter (both named Edith Bouvier Beale), cousins of Jacqueline Kennedy Onassis, who had been discovered living in epic squalor in East Hampton, N.Y.

The show (which has a book by Doug Wright and songs by Scott Frankel and Michael Korie) was a mixed bag, unwieldy in tone and structure. But portraying both Edith Sr. (in the first act, set in 1941), and her middle-aged daughter in the 1970’s (in the second act), Ms. Ebersole demonstrated how musicals can take you into psychological territory that no other form of entertainment can.

Especially when she was embodying the exhibitionistic younger Edie, whose personal style might politely be described as eccentric, Ms. Ebersole shimmered with multifaceted talent and intensity. Playing a sad character, she somehow left me feeling improbably happy. Whenever she was onstage, I began to wonder if the announcements of the death of the musical as an indispensable art weren’t, once again, premature.