Here's one tribute/concept album that lives up to the hype. Celebrating the label's 25th anniversary, Roadrunner Records elected four "team captains"--former Fear Factory [ tickets ] guitarist Dino Cazares, Machine Head [ tickets ] frontman Robert Flynn, Trivium [ tickets ] vocalist Matt Heafy and Slipknot [ tickets ] drummer Joey Jordison--to write and produce songs using different musicians for each track.

The resulting 18 songs feature 56 musicians from 44 different Roadrunner bands, past and present, and serve as one mother of a "Metallurgy 101" course.

As expected, you get plenty of monster-growl vocals (courtesy of the likes of Chimaira [ tickets ]'s Mark Hunter, Decide's Glen Benton and Cradle of Filth's Dani Filth) and blistering guitar solos (Sepultura's Andreas Kisser, Annihilator's Jeff Waters and Obituary's James Murphy). But that doesn't mean the album lacks surprises.

Kisser's acoustic-guitar opening on "The Enemy" recalls vintage Metallica, while the Cazares-penned "The End" is certainly more melodic that you would expect from a pure metal release.

The most infectious song--by far-is the Jordison-penned, mid-tempo rocker "No Way Out." Featuring none of the machine-gun drumming Jordison is famous for, the foot-stomper truly highlights why he is one of the principal songwriters in Slipknot. Originally a guitarist, he could probably make some cool cash cranking out killer riffs for more commercially minded projects, if he wanted to.

Mercilessly loud and diverse, metalheads everywhere should be moshing over each other to get to this.