SINEAD O'CONNOR, "THROW DOWN YOUR ARMS" (THAT'S WHY THERE'S CHOCOLATE AND VANILLA) *** 1/2

SINEAD O'CONNOR, "COLLABORATIONS" (CAPITOL) ***

Earlier this year, controversy-plagued Irish singer Sinead O'Connor announced that she'd be retiring from music, which would have been an irreplaceable loss: For all of her troubles over the last 15 years, she remains one of the most powerful voices in popular music. Now she has returned with a promise to concentrate on "spiritual music," which she defines on her welcome self-released comeback as reggae, produced by two masters of the genre, Sly and Robbie.

This may seem like an odd move to some, but it won't come as a surprise to O'Connor's still considerable hard-core following: Generally overlooked in the pillorying the artist received in 1992 after her infamous pope-bashing appearance on "Saturday Night Live" was the fact that she had torn up a picture of John Paul II after performing "War," a song popularized by Bob Marley, and that on her then-current "Am I Not Your Girl?," she had included a hidden track paraphrasing the teachings of the Rastafarian religion, which criticizes the Catholic Church for oppressing minorities. (Jamaicans believe the Church condoned the slave trade; O'Connor is of the opinion that it treats women like slaves.)

O'Connor reprises "War" as the last of a dozen powerful reggae covers here, which also include Lee "Scratch" Perry's anti-imperialist anthem "Vampire" and Peter Tosh's "Downpressor Man," making "Throw Down Your Arms" as much of a fiery political statement in support of the downtrodden Third World as it is an inspiring commentary on the power of faith. ("He will take us by the hand / And lead us to the wonder land / If we can't be good, we'll be careful / And do the best we can," she sings in "Y Mas Gan.")

Though she makes no attempt to mask her Irish accent or hide the fact that her roots lay in a completely different culture, O'Connor's bell-like soprano and passionate delivery allow her to claim these reggae jams as her own as thoroughly as she claimed the traditional Irish folk songs on her last covers album, "Sean-Nos Nua" (2002). Meanwhile, the Riddim Twins Sly and Robbie wisely keep the arrangements and slinky grooves stripped down and simple, the better to maintain the spotlight on that voice.

Meanwhile, O'Connor's old label Capitol provides further evidence of the singer's ability to adapt to almost any genre with "Collaborations," a 17-track compilation full of rarities and unexpected treats released last summer. The big names here may hold the most allure for many listeners -- included are "Blood of Eden," O'Connor's moving duet with Peter Gabriel; "I'm Not Your Baby," which she crafted with fellow Irishmen U2, and "Harbour," a track produced by Moby -- but the real winners are strange but nonetheless effective experiments with the likes of Massive Attack, Jah Wobble and Afro Celt Soundsystem.

THE GO! TEAM, "THUNDER, LIGHTNING, STRIKE" (COLUMBIA) *** 1/2

Performing at the Intonation Music Festival last summer, the Mercury Prize-nominated English dance-pop sextet the Go! Team stole the show and provided the highlight of that inspiring event when its MC, cheerleader and lead vocalist Ninja pulled a group of young African-American kids from the neighborhood onstage and they all pogoed and boogied frantically as the group churned out its irresistible mix of dance rhythms, hip-hop flavorings and rock 'n' roll energy.

Laced with well-chosen samples, heavy on the funky R&B horns, the band's debut was first issued in the U.K. last year, but is only now getting its official American release in slightly reworked form, with several tracks remixed to remove samples that hadn't been cleared and two additional songs added to the original.

It remains an effervescent and positively giddy high-energy joy, cheerfully blurring genre boundaries (not for nothing has the band garnered comparisons to everyone from the Jackson Five to Sonic Youth) to arrive at a unique and wonderful mix on unforgettable grooves such as "Panther Dash," "Feelgood by Numbers" and "Air Raid Guitar."