ISIS

They've toured with Tool and performed at the Museum of Contemporary Art in Los Angeles. They've collaborated with the Scottish dream-rock outfit Aerogramme and been invited by Mogwai and Tortoise to play the prestigious "All Tomorrow's Parties" UK music festival. And with their ferocious fusion of devastating power and pensive beauty, the Boston-by-way-of-LA outfit ISIS has been characterized as everything from "art metal" beacons to leaders of a post-psychedelic "metalgaze" movement. In short, the descriptions have been as richly varied as ISIS's music has been during the band's 10-year tenure.

"It's not like we're necessarily genre-hopping from one style to another, but we have incorporated a lot of different influences into our music," says singer-guitarist Aaron Turner over the phone from a tour stop in Richmond, Va., nearly halfway into a six-week headlining North American tour that brings ISIS to the Middle East in Cambridge for a pair of shows tonight and tomorrow. "There's a lot of bands who are easily defined because they're always operating in one mode, and that type of purity or narrowness has a tendency to build a niche audience. We may not be the most accessible band in the world, but I think there's enough dynamic and emotional range in our music that we can appeal to a pretty good cross-section of people."

ISIS is touring in support of its fourth full-length album, "In the Absence of Truth," out now on Ipecac Recordings, the California-based label founded and run by ex-Faith No More frontman Mike Patton and former Alternative Tentacles label manager Greg Werckman . The latest album builds on the sonically expansive, densely layered territories the band first explored a decade ago. There is both darkness and light here, earthbound ferocity and free-floating grandeur, and constantly moving, inexorable undertow to tracks such as "Wrists of Kings" and "1,000 Shards," the latter of which eventually disintegrates into the instrumental ether of "All Out of Time, All Into Space." Small wonder that past ISIS albums have been titled both "Oceanic" and "Celestial."

That duality of approach is precisely what attracted Ipecac's Werckman to ISIS. "They don't fit into any one genre," Werckman says via e-mail. "It is hard rock or metal at times, yet they absolutely don't fit with metal bands. It is beautiful and atmospheric yet they absolutely are not a shoegazer band. As great as they sound, the icing on the cake is the type of people they are. Absolutely unassuming. They know what they want and are perfectionists but they are as grounded as any band I have ever worked with."

As abstract and murky as "In the Absence of Truth" is at times -- Turner's spleen-venting bellow doesn't exactly make deciphering his lyrics easy -- he claims the disc's title and narrative thread have to do with the manipulation of truth, fact, and information through the ages. Tempting as it might be to tie the disc's title into the current state of politics and world affairs, the album is "not totally anchored to current events," says Turner. "In fact, I wanted to pick something that had a much more universal scope. I do think that there needs to be some open dialogue about what's going on in the world at the moment, but I don't want ISIS to be an overtly political mechanism. I wanted the themes to be a bit more open-ended and leave some room for interpretation."

Although he balks at lumping ISIS in with other high-profile Massachusetts-born metal acts such as Killswitch Engage, Staind, and Godsmack to name a few, Turner believes that the genre is particularly healthy right now. "I wouldn't necessarily associate us with [those] bands," he says, "but any time there's a surge in popularity in any given genre, anyone who falls under that umbrella, whether they're closely related or not, will benefit from that. It's not something we're going to shy away from."

In fact, ISIS -- which also includes guitarist-keyboardist Clifford Meyer, bassist Jeff Caxide, drummer Aaron Harris, and guitarist Mike Gallagher -- has at least as much to do with the post-rock psychedelia of bands such as Dead Meadow and the aforementioned Mogwai as it does heavy metal forefathers like Black Sabbath or descendants like Kyuss or Queens of the Stone Age.

"I've always been interested in adventurous music," says Turner, 29, who was born in Springfield and grew up surrounded by older siblings who are also working musicians (his brother, Charley, contributes vocals on the new ISIS album; his sister, Jessie Turner, is an accomplished singer-songwriter). An early influence was his parents' jazz library, as was his older brother's collection of classic rock albums: Led Zeppelin, Jimi Hendrix, Black Sabbath, the Doors.

"Those groups were pretty adventurous for their time, but even within their respective catalogs, I was always drawn to the stuff that was more epic in scope and often very heavy in terms of atmosphere and texture," he says. "I really know why I always gravitated toward things that were a bit darker or more esoteric and out there. With everybody else in ISIS, that's true too, and I think that's why we've been able to function as well and as long as we have."

BITS & PIECES. Tonight Andrea Gillis is at Johnny D's. Taxpayer is at T.T. the Bear's. Los Diablos are at the Plough & Stars for the first of two shows (the second is tomorrow night). Tomorrow The Bleedin' Bleedins are at Great Scott. The Ramblin' Souls are at the Abbey Lounge. The Franc Graham Band is at Toad. Tuesday The Autumn Defense (featuring members of Wilco) are at the Middle East Upstairs. DeSol is at the Paradise Lounge. Wednesday The Young Knives are at Harpers Ferry. The Dennis Brennan Band is at the Lizard Lounge. Thursday Read Yellow plays its final show at the Middle East Upstairs. Helms is at Great Scott. Jen Kearney & the Lost Onion are at the Lizard Lounge.