The second Queens of the Stone Age album, Rated R (as in the movie rating; its title was changed from II at the last minute before release), makes its stoner rock affiliations clear right from the opening track.

The lyrics of "Feel Good Hit of the Summer" consist entirely of a one-line list of recreational drugs that Josh Homme rattles off over and over, a gag that gets pretty tiresome by the end of the song (and certainly doesn't need the reprise that follows "In the Fade").

Fortunately, the rest of the material is up to snuff.

R is mellower, trippier, and more arranged than its predecessor, making its point through warm fuzz-guitar tones, ethereal harmonies, vibraphones, horns, and even the odd steel drum.

That might alienate listeners who have come to expect a crunchier guitar attack, but even though it's not really aggro, R is still far heavier than the garage punk and grunge that inform much of the record.

It's still got the vaunted California-desert vibes of Kyuss, but it evokes a more relaxed, spacious, twilight feel, as opposed to a high-noon meltdown.

Mark Lanegan and Barrett Martin of the Screaming Trees both appear on multiple tracks, and their band's psychedelic grunge -- in its warmer, less noisy moments -- is actually not a bad point of comparison.

Longtime Kyuss fans might be disappointed at the relative lack of heaviness, but R's direction was hinted at on the first QOTSA album, and Homme's experimentation really opens up the band's sound, pointing to exciting new directions for heavy guitar rock in the new millennium.