Our Lady Peace's upcoming fifth album will mark the beginning of a new chapter in the band's 10-year history, according to drummer Jeremy Taggart.

Speaking via telephone from Vancouver, where the group is mixing the as-yet-untitled new disc with producer Bob Rock, Taggart called the 12 completed songs "by far our best record" and a radical departure for OLP.

"We recorded it in Maui, and we are mixing it in The Warehouse in Vancouver. We're just trying to finish it. When it comes out, we're not sure. Hopefully summertime, late summer," Taggart told JAM! Music.

"We're just really happy with it. It is by far our best record. I'm sure you hear this from every single band that are making a new record. But this, for me, is such a departure, in terms of the sound and simplicity of the songs. It is a completely brand new thing for me."

Among the working titles for songs on the album: "Story About A Girl," "Somewhere Out There", and "Made Of Steel."

Early on in the recording of the new disc, the band split with founding guitarist Mike Turner. Jamie Edwards, who has been playing second guitar and keyboards with OLP, has filled in on the record. No decision has been made about a permanent replacement, Taggart said.

The group took a break from work on the new album to perform at last year's "Music Without Borders" concert at Toronto's Air Canada Centre, which will go down as Turner's final gig with the band.

"Basically, his vision and our vision separated," Taggart said of Turner's departure.

"Obviously, there was definitely a feeling for both parties that the vision was changing. The stuff he was writing was a lot different than the stuff we were seeing as a band. The stuff he was writing was cool, but it was different. That is just what happens in relationships".

Despite the disruption of a lineup change, Taggart said the new music has added a new charge to the band -- something he credits to the influence of producer Rock, who began his career with The Payolas and has gone on to produce Bon Jovi, Bryan Adams, The Cult, Metallica, and Aerosmith.

"I am so revitalized. Everyone is so revitalized," Taggart said.

"Bob Rock came in with a completely different perspective. Someone of his stature, a world-class producer and a world-class guy, he pushed us and coached us into a place we have never been before.

"It was so new for us. It definitely marks a new chapter in our lives. Maybe Chapter Two. It feels that different. Bob has so many great guitars and amps and drums, sonically it sounded so different."

More than anything, Rock's studio approach freed the band to be more spontaneous. During the group's first day at Rock's Maui studio, they wrote a new song and reco rded it the same day -- a first for Our Lady Peace.

"There's a little more energy on tape than on previous records, you know. The songs are simpler. They are not as thought out," he said.

Taggart said P.O.D. vocalist Sonny Sandoval was to make a cameo on the album -- his band had tried to land singer Raine Maida for a similar guest spot on P.O.D.'s album -- but the timing couldn't be worked out between either band's touring and studio commitments.

As for when the album will be in stores and when Our Lady Peace will get back out on the road, Taggart said that the intense work of mixing the new disc is preoccupying them, and no timetable has been set up.

"I'd like to get on the road as soon as possible," he said. "But who knows?"