A Perfect Circle’s modus operandi has always been that the group is not a side project. Functioning like a band of disgruntled art students, the group helped push the brooding prog-rock genre a little further into the limelight with the successful Mer de Noms, a 12-track collection of murky ballads and bottom-heavy grooves. Three years later, the band returns with Thirteenth Step, an album conceptualized as a diary of recovery and rehabilitation.

Lead singer Rev. Maynard James Keenan, who divides his time between A Perfect Circle and seminal proggers Tool, has always received a bulk of the press for A Perfect Circle. Maybe it’s his ever-growing collection of wigs or his mysterious stage demeanor, but the general public quickly associates A Perfect Circle with Keenan. The real credit, however, belongs to chief orchestrator and guitarist Billy Howerdel, former guitar tech for Tool, among others.

In his compositions, Howerdel places as much emphasis on the bass as he does on his guitar, a tendency quickly noticed on Thirteenth Step. Rather than have the bass play tic-tac-toe with a blasting guitar, Howerdel reverses the order, having the guitar function as background. It’s this subdued, low-end resonance, along with Keenan’s unmistakable vocals, that give A Perfect Circle and Thirteenth Step an identity all their own.

Functioning like a revolving door, A Perfect Circle’s physical composition has undergone changes since the success of Mer de Noms. The live incarnation of the progressive supergroup now includes Howerdel, Keenan, former Marilyn Manson bassist Jeordie White (Twiggy Ramirez), drummer Josh Freese and former Smashing Pumpkins guitarist James Iha.

Studio contributions on Thirteenth Step came from former A Perfect Circle members Paz Lenchantin (bass) and Troy Van Leeuwen (guitar), as well as Nine Inch Nails guitarist Danny Lohner, who at one point filled A Perfect Circle’s vacant guitar slot.

“The Package” gets things going with a dense bass line and percolating guitars that provide the bare-bones environment for Keenan to lament about the selfish, lonely world of addiction, singing, “Just give me what I came for and I’m out the door again.” The track eventually explodes in its latter half with one of the few points in the album where the guitar is at the forefront.

Lead radio single “Weak and Powerless” may exude a more feeble sound than fans of Mer de Noms‘ lead single “Judith” may appreciate, but the song is an accurate depiction of the chugging, layered introspection of Thirteenth Step.

Casual fans of Mer de Noms will initially be quite disappointed with Thirteenth Step. There aren’t the meaty bar chords of “Hollow,” the in-your-face vigor of “Judith” or the ethereal beauty of “3 Libras,” but there are plenty of tunes that slowly build on you, settling in your system, allowing you the time to ruminate and better appreciate what the group was hoping to achieve.

“The Noose” may not scream commercial airplay, but this is headphone music, the kind of slow, swelling ballad that takes time to appreciate. “Blue” may be the best bet for a follow-up single. Disoriented guitars regain their composure to deliver a rich, melodic progression that weaves its way through the song, making it one of the album’s standouts as well as one of the tracks that could have commercial potential.

“The Outsider” is perhaps the most overtly aggressive tune on Thirteenth Step, with Keenan’s vocals taking a caustic front on top of ruffled guitars that recall the energy of old work like “Judith.” This is definitely WJJO material, but not the best work on the album.

Casual fans and enthusiasts will be magnetically drawn to “The Nurse Who Loved Me,” a charming lullaby with witty lyrics like, “She’s got everything I need — pharmacy keys,” but any fan of the ultra-magnificent-but-disbanded Failure will instantly recognize the song as one of the centerpieces from Fantastic Planet, Failure’s last hurrah and one of the truly great albums of the 1990s.

Anyone who doesn’t have that album should acquire it by any means possible. Ken Andrews and Greg Edwards’ composition lives on in alternate form, and it’s a shame that critics and fans will come to appreciate this song in its new life when they should have embraced it years ago. Many will simply believe the track is an A Perfect Circle original, and a quick read of www.rollingstone.com reveals that even the most elite critics have no clue about the origin of the song.

At 12 songs, Thirteenth Step is one step short of being exceptional. The album will grow on you, but a short instrumental (“Crimes”) and the lifting of Failure’s “The Nurse Who Loved Me” reduce the album to 10 songs that took three years to make — much too long for a product of varying quality.

Grade: B