The world may never know why Beyonce Knowles, Kelly Rowland and Michelle Williams, collectively known as Destiny's Child, really decided to reunite and create the album "Destiny Fulfilled."

Maybe the R&B threesome just wanted to make good on a promise: They disbanded not long after producing 2001's "Survivor," but vowed to reassemble after trying out solo projects. Perhaps manager Mathew Knowles nudged the women, thinking he could borrow from his daughter's superstardom in order to advance the careers of Rowland and Williams. Or it could be that Beyonce's mom, Tina Knowles, who is also the group's mad stylist, hoped that a reunion would give her a chance to whip up more of those fly matching costumes that the girls once favored.

Speculating is more fun than accepting the canned comments offered in interviews by the women of DC: They're back because they missed each other and enjoy making music as a team. But after listening to their rapprochement record -- a smooth, unexpectedly soulful, all-grown-up album -- it seems that their simple explanation might be closest to the truth.

On "Destiny Fulfilled," the three-part harmonies are sweeter than ever and the songwriting -- some of it by Beyonce and Rowland -- is evocative and strong. And being thrown together again highlights the individual strengths of the singers, who share executive-producer credits on the album, along with Papa Knowles, of course.

Beyonce Knowles, who stands to gain the least from rejoining the group, refuses to slack off simply because she's the star of the show. She is the album's vocal producer as well as the brain behind its concept. The group's latest was designed as a concept album that travels the course of a rocky relationship -- every song documenting a different stage in its progression.

Each woman is truly herself here, or at least fully immersed in her chosen persona. Knowles is the sexy Southerner with the sultry voice to match, Rowland the firecracker with clear, crisp vocals as straightforward as her no-nonsense attitude, and Williams, whose voice and lifestyle are most outwardly influenced by the church, seems even more sanctified when standing next to her partners.

The first two singles, both produced by Rodney Jerkins, don't mesh with the laid-back vibe on the rest of the record, but the dance tracks are welcome intrusions. Just when marching-band percussion was becoming an urban music cliche, the sound is reinvented on "Lose My Breath." The women huff, puff, coo and moan over the drum corps beat, creating a sound that is homecoming-game-meets-harem. "Soldier," featuring rappers T.I. and Lil' Wayne, is a thumping, Southern-fried paean to the joys of thug passion.

But after those songs are out of the way, "Destiny Fulfilled" is strictly a grown and sexy affair. Tons of old soul-music samples, handled with care by production powerhouses including 9th Wonder and Rockwilder, help create the feel. Surrounded by those snippets, the women are closer in style to the Supremes than the pre-packaged model they previously resembled.

On "Is She the Reason," a chunk of an old Melba Moore tune provides a foundation for pondering infidelity and a glut of lonely nights. "Girl" finds Knowles and Williams, with a little help from the Dramatics, trying to persuade Rowland to leave her no-good man. And "If" owes its neo-soul sound to weepy piano borrowed from Natalie Cole's "Unforgettable." The tinkling softens the blow when Knowles tell her neglectful beau, "If you get to feeling stressed up in your chest thinking that you're about to lose, baby it's true."

The album isn't completely devoid of the growing pains that pop maturity can bring. "T-Shirt" is a pathetic picture of the women clinging to their boyfriends' Hanes Beefy T's for comfort, and "Cater 2 U" has them running baths, rubbing feet and making dinner for their fellas. The spunk of "Bills, Bills, Bills," when the women announced that they needed men only to keep their lights on, was a lot more fun. Also disappointing is the lack of a Jay-Z cameo (although there is a juicy shout-out in Knowles's acknowledgments that can be meant only for him).

But the biggest letdown is the absence of a girl anthem. The fist-pumping feminist songs that made the Destiny Children household names are no more. The omission is odd considering that adult women acquainted with heartache haven't typically made up the bulk of the group's fans.

Knowles, Rowland and Williams have managed to change their shared fate with their sixth disc. They are R&B divas catering to teeny-bopper tastes no more. And, provided they can find an audience that appreciates their transformation, they are well on their way to fulfilling their destiny.

Beyonce Knowles, Michelle Williams and Kelly Rowland reunited for the first Destiny's Child CD in three years.With this CD, Beyonce, Kelly and Michelle no longer cater to teeny-boppers.