There comes a time in the career of a famous rock band when its members are inexorably drawn to the idea of recording some homage to their influences, or perhaps a tribute to favored colleagues. For Metallica, this was the time.

Whether their music is careening like a runaway heatseeker missile or they're just working the heavy-metal stomp-and-howl, Metallica's James Hetfield, Kirk Hammett, Jason Newsted and Lars Ulrich have never been anything less than tremendously agile musicians. That's a given, even when the hard-rocking quartet could get away with coasting.

This two-CD collection -- over two hours of cover tunes -- might have been one of those opportunities to dash off something quick and easy. Instead, it's a chance for the band to get back to the raw-fusillade approach to music from their early Master of Puppets days, after the more recent, more polished efforts such as their self-titled, multi-platinum 1991 album.

With one exception, the first disc of Garage Inc. was recorded in a recent three-and-a-half-week, post-concert tour burst. The ringer is an overly reverent, all-star version of Lynyrd Skynyrd's lament, "Tuesday's Gone," recorded for a radio broadcast. (Les Claypool of Primus, John Popper of Blues Traveler and Skynyrd's own Gary Rossington were among those sitting in on the session.)

But the rest of that first disc, subtitled "New Recordings '98," takes on a panoply of material from artists that range in diversity from lumpen, prole-metal band Mercyful Fate to metal-pop cult faves the Misfits to aggro-punkers Discharge to blue-collar rocker Bob Seger. And what is truly remarkable is how comfortable Metallica sounds on most every number, despite the disparity in genres.

Singer Hetfield's growl services the darkly-menacing "Lover Man" from Aussie Goth-blues maven Nick Cave. Then Hetfield turns around and taps into the sorrow of the nomadic rocker on Seger's "Turn the Page." If it's hell-bent guitar you want, don't fret. Leave it to Hammett, who stretches out on a monumental version of "Astronomy" from the songbook of the guitar-driven riff-rock monsters Blue Oyster Cult.

Throughout the project, the rhythm section of bass player Newsted and drummer Ulrich hammer and thump with verve. The more metallic the composition (Diamond Head's "It's Electric," Black Sabbath's "Sabbra Cadabra"), the better they serve it up.

"Whiskey in the Jar," the Gaelic traditional rearranged by '70s Irish hard-rockers Thin Lizzy, is the high point of Garage Inc. Played with passion and dynamism, it just rears back and roars.

"New Recordings '98" was assembled at the Plant Studios in Sausalito, Calif., with producer Bob Rock -- a comfortable match after his work on other Metallica releases.

The other disc was even easier to put together -- previously-issued Metallica covers of songs first done by artists such as speed-metal icons Motorhead ("Overkill"), anarchy-loving punk-rockers the Anti-Nowhere League ("So What"), new-wave art-punks Killing Joke ("The Wait") and -- gasp! -- the pop-eratic chart-toppers Queen ("Stone Cold Crazy"). Completists will freak over this de facto compilation of B-sides, EPs and rarities. (For instance, the Queen track was recorded for Elektra Records' 40th Anniversary anthology.)

Metallica seem to have approached Garage Inc. with a spontaneity that cuts to the bone of the material. If it just happens to have an effortless feel to it, that's part of its allure.