Tool releases are a big deal in the world of music. They sell millions of copies and influence thousands of artists, dozens of whom inevitably make it to the mainstream. Three years from now, 10,000 Days will have left its impression on music, but on May 2 it made its mark.

With each imminent Tool album comes the question, “What will Tool sound like now?” It’s a fine thing to watch a band evolve, but the distanced, intellectual turn 2001’s Lateralus took left some fans feeling a twinge of disappointment because the album’s rhythms and lyrics were noticeably more cerebral and less visceral than those on 1992’s Undertow and 1996’s Ænima.

During the gap between albums, the guys from Tool were seen cavorting with members of Meshuggah and are admittedly big fans of the band’s music, sharing the stage with them for a time during the Lateralus tour. The friendship makes itself known on 10,000 Days. Meshuggah is known for masterfully stacking severely downtuned, dissonant melodies on top of heavily distorted guitars playing tight, monolithic rhythms over drums that are played in anything but standard timing. 10,000 Days still has the comfortable crunch Tool is known for, but it’s significantly heavier than Lateralus and has a newfound depth.

10,000 Days’ first single and opening track, “Vicarious,” is a punishing, aggressive and seamless synthesis of Tool’s past. Easily the album’s most visceral track, it opens with a lilting guitar a la the titular effort of Lateralus atop a distorted, palm-muted arpeggio reminiscent of “The Patient” from the same album, and packs the punch of Ænima’s title track. As the introduction winds down, a dramatic drop-in reminiscent of “Parabol”/”Parabola” introduces a rhythm that’s patently Tool and, though it feels like it would have fit in on Lateralus, contains the edge that made songs like “Sober” popular and satisfying.

Unfortunately, the track’s mood and delivery are unmatched anywhere else on the album. That’s not to say the rest of the record fails, but rather that “Vicarious” may be one of the best songs the band has ever produced. Even for a group with the talent and vision of Tool, it’s hard to maintain that kind of power for the 70-plus minutes that Tool albums run.

It’s been said that Tool is Danny Carey’s band. The man puts on an exhibition every time he sits down; he’s a drumming demigod, and he’s in top form throughout the album. His pace and accuracy are astonishing as usual, and his work on 10,000 Days is bound to inspire an entire generation of drummers and air drummers alike. This notion is especially credible on the second track “Jambi,” a love-it-or-hate-it piece full off-kilter rhythms and strange changes in tempo.

So, what about the lyrics? In the minds of many, vocalist Maynard James Keenan was the wild card on this album. A significant number of those who had problems with Lateralus thought he spent too much time on top of rather than in the mix. Those who paid attention to his efforts with A Perfect Circle would have noticed he’s increasingly utilized vocal filters more as he’s aged. Well, his effects are back, but so are his Ænima-era lyrics, singing style and place in the mix. This time around, the words go straight to the gut instead of above the head.

The third and fourth tracks, “Wings for Marie (Part 1)” and “10,000 Days (Wings pt. 2),” are a sterling example of this and a two-part eulogy honoring Keenan’s departed mother, Judith Marie Garrison, the woman referred to in A Perfect Circle’s “Judith.” An aneurysm left Garrison paralyzed and complications from it led to her death 27 years – approximately 10,000 days – later. It’s during these tracks that the atmospheric qualities of 10,000 Days begin to emerge, the latter featuring thunderclaps and the pitter-patter of falling rain. While the tribute is extremely touching, the pair of songs loses something without knowledge of Maynard’s familial hardships.

Each full-length Tool release has featured one song that’s noticeably more belligerent than anything else on the album. Undertow had “Swamp Song,” Ænima had “Hooker With a Penis,” Lateralus had “Ticks and Leeches,” and 10,000 Days has “The Pot.” Boasting the lyrics, “Who are you to wave your finger? / So full of it / Eyeballs deep in muddy waters / F—in’ hypocrite / Liar, lawyer – mirror, show me, what’s the difference? / Kangaroo done hung the guilty with the innocent,” and a notable eight-second scream near the end of the track, “The Pot” is an effective counter to any criticisms that Tool or Keenan may have gone soft.

“Lipan Conjuring” is the first disappointment on the album. It and the last track, “Viginti Tres,” get an F for filler.

Thankfully, the next pair of tracks, “Lost Keys (Blame Hoffman)” and “Rosetta Stoned,” makes up for the missteps. The former is a cryptic conversation between a doctor and nurse about “a gentleman in Exam 3” who has an unidentifiable problem. The latter is an epic, paranoid and schizophrenic 11-minute confessional by the patient in which he details his situation. Suffice it to say, the reference to Albert Hoffman is apt.

“Intension” and “Right in Two,” the ninth and tenth tracks, mark the album’s other low points. While both decent songs, they tend to drag. The second is markedly more inspired than the first, featuring an extended tabla solo, though there’s a riff and accompanying beat flagrantly cribbed from Ænima’s “Forty-Six & 2” around the six-and-a-half-minute mark.

So what’s the verdict? Well, while there’s plenty to like, the album’s track progression is strange, almost clunky, resulting in songs or pairs of tracks that stand out. It feels like it meanders about without a conclusive destination. Yet, regardless of its shortcomings, 10,000 Days is one of 2006’s best releases and a worthy addition to the Tool treasury. It may not be perfect, but it’s perfectly listenable.

Grade: A

‘Tool’ box

Undertow

Sure, Opiate was released more than a year prior, but this is the album that introduced Tool to the world and altered the landscapes of metal and rock, going double platinum in the process. The band’s first full-length studio effort, Undertow spawned the single “Sober,” which tore across the airwaves in a censored frenzy. Thirteen years after its release, the track continues to receive respectable airtime and remains Tool’s most easily recognizable song. It’s just that good.

Grade: A-

Ænima

The second rendezvous in rock’s love affair with Tool, Ænima provided fans with a much more enigmatic, well-produced record to digest. It also silenced detractors and kicked the notion of a sophomore slump flat on its ass. The album went triple platinum and marked the band’s initial foray into album art that was as impressive as the music it encased. The front of the jewel case featured a lenticular frame that animated some of the pictures contained in the liner notes.

Grade: A+

Lateralus

Coming a whopping five years after Ænima, Lateralus showcased a more mature and, for the most part, notably less sardonic band than the previous two records. Eastern influences are obvious throughout the album, and its lyrics demand far more “think” than “feel.” Those factors, along with lead singer Maynard James Keenan’s work with A Perfect Circle, disillusioned some longtime fans, but enough stuck around to buy more than two million copies.

Grade: B