Black Sabbath is one of the most influential bands in rock. You can hear the Sabbath strains in heavies ranging from the Rollins Band to Metallica.

But Black Sabbath is different from rock's other big influences like the Beatles, the Velvet Underground, Sly Stone and the Sex Pistols:

Sabbath is still making records. And touring. With the release of Dehumanizer, Black Sabbath features a classic lineup not seen in more than 10 years.

Bassist Terry "Geezer" Butler and guitarist Tony Iommi -- who founded the band with Ozzy Osbourne in Birmingham, England in the late '60's -- are back with singer Ronnie James Dio and drummer Vinny Appice. They are at Massey Hall this Thursday.

On the phone from Miami, where Sabbath kicked off a North American tour last week, Geezer Butler, now 43, reflects on the reunion and the "dark" Sabbath sound.

"Musically, it's back to the original sound of Sabbath; that's what we all wanted", he says.

"Lyrically, I think Ronnie has advanced. So it's a bit of both. Going back to the roots, yet moving forward."

Butler laughs when asked how he feels about being a founder of the world's best loved metal band.

"Um, it makes you feel old", says the bassist. "No. It's really good, 'cause after all the years of slagging from the critics and everything, the bands are naming us as the major influence on them."

"It's especially good because it keeps our sound sort of fresh and current."

Keeping current on "Dehumanizer", Black Sabbath takes a lyrical stab at the mordern demon of technology, having essentially made a concept album about the computerization of humanity.

Says Butler: "Ronnie and myself sat down to discuss lyrical directions, and he didn't want to do all the dungeons and dragons and rainbow stuff, and neither did I. So we said, 'Let's deal with what's going in the world now.' There was loads of material to delve into and write about."

With "Time Machine", an AOR hit from the Wayne's World soundtrack, and a long-awaited tour under way, Black Sabbath has reason to be pleased. However, it all almost didn't happen.

"After the first six months we didn't really think the sessions were working", explains Butler. "It wasn't until Vinny came back into the band that we really sat down and jammed for about eight hours every day. It sort of took off from there, really. The first six months was a bit of a waste of time, just feeling each other out and being a bit too polite with each other."

"What we have learned is that if you keep polishing the work, you lose the soul of the band", says Butler.

"Plus, we knew that we weren't going to be played on radio, so we didn't have to try to be commercial."