Lurking in the background, DJ Mathematics has comfortably let the more gregarious members of his famous hip-hop ensemble - the Wu Tang Clan - hog the spotlight during the group's off years.

But following 2004's greatest hits compilation, Mathematics sticks with a dependable formula for his sophomore release, "The Problem."

Method Man, Inspectah Deck, Rza, Ghostface Killah, Gza, Cappadonna, Raekwon, Masta Killa, U-God and Ol' Dirty Bastard, all of whom contributed to the Wu's ear-bending mix of down-tempo rhyming and relentless dance-floor bounce, make guest appearances on the album's 15 tracks. And these surprise appearances end up being one of the album's greatest strengths.

The triple scoop of Method Man on "John 3:16," "Rush" and "Spot Lite," echoes the driving, staccato rhymes that typifies Meth's solo masterpieces ("Judgement Day," "Tical") and his fiery collaborative work with Redman ("Fire Ina Hole," "Da Rockwilder").

Ol' Dirty Bastard makes one of his final recorded appearances on the Mary J. Blige "All Night Long"-spiced "Break That," while new kids Eyeslow and Ali Vegas give "Winta Sno" a slow serpentine rap that recalls Nate Dogg on Eminem's "Never Enough." Buddah Bless and Angie Neil help deliver the smooth grooves on "Two Shots of Henny," and Wu mates Ghostface and Raekwon show up on the tub-thumping "Real Nillaz." Mathematics even finds time to imbue the disc with some cinematic flair on the synth-laden, operatic, "Tommy," which features Angie Neil on background vocals. And the funk-infused rap Bald Head and Starr exchange on " Coach Talk" gives the disc some much needed sex appeal.

"The Problem" makes a few missteps though.

Hot Flames stalls on the slow rolling "Can I Rise," while lines like, "Yo, my life's like a story, I'm gonna let it be known," sang by T-Slugz on "Bullet Scar," hit the dance floor with a thud.

But with his all-star lineup, Mathematics hits more than enough home runs to remind listeners why the Wu Tang, both together and on their own, are so great to begin with.

Track Listing:

1. Intro
2. C What I C ft. T-Slugz & Eyeslow
3. Strawberries & Cream ft. Allah Real, Inspectah Deck, Rza & Ghostface
4. Can I Rise ft. Hot Flames
5. John 3:16 ft. Method Man & P.I.
6. Winta Sno ft. Eyeslow, L.S. & Ali Vegas
7. Two Shots Of Henny ft. Buddah Bless, Angie Neil, Hot Flames, Eyeslow, P.I & Allah Real
8. Bullet Scar ft. T-Slugz
9. Real Nillaz ft. Ghostface, Buddah Bless, Eyeslow & Raekwon
10. Coach Talk ft. Bald Head
11. Rush ft. Method Man & Gza
12. U.S.A ft. Ghostface, Masta Killa, Todd, P.I., Eyeslow & Hot Flames
13. Tommy ft. Allah Real, Eyeslow, Angie Neil & Bald Head
14. Break That ft. Ol' Dirty Bastard, Masta Killa & U-God
15. Spot Lite ft. Method Man, U-God, Inspectah Deck & Cappadonna