Now, Slash follows in Iommi's footsteps, even including three of the same guest stars (Osbourne, Ian Astbury of The Cult, and Dave Grohl). But while there's plenty to like on the resulting album, the material doesn't really live up to expectations: Slash's abilities with a six-string are not in question, but he's much better at playing one type of music (dirty, heavy, blues-based rock 'n' roll) than any other -- meaning that he can't write well for twelve different singers with very different styles, as he attempts to. And a few of his singer choices are just plain bad, in and of themselves.

The good thing about this record is that when he does what God put him on this earth to do -- tear stuff up with a Les Paul and a Marshall -- Slash truly excels. In the very first track, "Ghost," he resurrects the classic Guns N' Roses guitar tone, which we haven't heard much since the days of Slash's Snakepit, at least not in its purest form. Sure, Velvet Revolver put out two good records, but Slash just ain't Slash without that old-school, midrange-heavy, tube/valve/magic sound coming from his amp. Vocals from Ian Astbury and a stomping AC/DC beat round things out to make this one of the album's more captivating tracks.

On the other songs, everything works out so long as two conditions are met: Slash doesn't stray too far from his strengths, and the vocalist delivers a good performance. Ozzy's track, "Crucify the Dead," passes this test; Slash doesn't s quite showcase his talents to the fullest, but until the solo, he plays some loud chords and stays out of the way for some great melodies on Ozzy's part. Chris Cornell's "Promise," a true blend of the former Soundgarden frontman's dramatic alternative style and Slash's gutter-rat rock ethos, also works well.

And however hesitant I am about Wolfmother -- are they irony-obsessed hipsters, or do they genuinely like '70s metal? if the former, they can go to hell -- Andrew Stockdale's contribution, "By the Sword," isn't half-bad. Lemmy's song, "Doctor Alibi," is nothing special, but hey, it's Lemmy and Slash on the same recording, which is pretty awesome by definition. "I Hold On," featuring Kid Rock sounding a little like Steven Tyler, is a down-home rock track with a little touch of raunch. "Saint Is a Sinner Too," a Spanish acoustic-guitar ballad featuring Rocco DeLuca, features a seldom-shown talent of Slash's (remember the outro to "Double Talkin' Jive"?) to great effect.

Unfortunately, not all the songs work out so well. As Slash has said in interviews, Fergie proves herself to be a great rock singer in "Beautiful Dangerous," but the bottom line is that the song itself is only mildly catchy. (And for some reason, the chorus melody reminds me a little of Lady Gaga's "Paparazzi," which can only be a bad sign.) Adam Levine of Maroon 5 does the best he can with the middle-school-dance ballad "Gotten," but it's still dreadful. "Watch This," featuring Duff McKagan and Dave Grohl, is an instrumental track that feels like a real song with the vocals left off. On "Nothing to Say," featuring M. Shadows of Avenged Sevenfold, Slash tries his hand at modern metal, with mediocre results. "We're All Gonna Die," featuring Iggy Pop, looks a lot better on paper than it sounds coming out of one's speakers -- however much Iggy and Slash seem like a match made in heaven, they don't really gel here, with uninspiring lyrics ("pee on the ground and jump around"?) and flat guitar riffs.

Easily the worst choice is Myles Kennedy -- the cheesy shrieker Creed hired to replace Scott Stapp when they became Alter Bridge -- and Slash gives Kennedy not one track, but two. The songs' foundations might have been fine in the hands of a better singer, but Kennedy (of course) proceeds to warp them into terrible, over-emotive modern rock. The man is the heir not to Robert Plant, as has often been claimed, but rather to Whitesnake-era David Coverdale. This is fine (I have a soft spot for awful, over-the-top pop-metal), but it makes Kennedy a poor fit for Slash's raw edge.

Worse yet, Slash has tapped Kennedy for his upcoming tour. For some reason, Slash seems to enjoy working with frontmen who have great ranges but generic styles -- which we saw also in Rod Jackson, the singer who made Slash's Snakepit's Ain't Life Grand such a middling effort.

There are so many singers who could have replaced Kennedy on Slash's roster, both on the record and on stage. Plant himself would have been great. Given the resurgent success that 1991's "Always on the Run" has enjoyed in guitar video games, a Lenny Kravitz collaboration almost seems to suggest itself. Chris Robinson of The Black Crowes would have turned the blues-rock track "Starlight" from an insincere ballad into a heartfelt ode to some woman or other. Steven Tyler stooped to appearing (and doing a poor job of acting) in the sitcom Two and a Half Men not too long ago, so he'd surely have been up for a song with Slash.

For Slash's hardcore fans, this isn't a terrible buy -- his guitar solos make even the songs that suck worthwhile. Most other rock fans, however, can skip this one, or at most download the better efforts.

-- Robert VerBruggen is an associate editor at National Review. You can follow his writing at http://www.google.com/profiles/robertv4311#buzz.