TORONTO — On the cover of "Mustaine," a new autobiography from the frontman of metal band Megadeth, a more youthful, almost-cherub version of Dave Mustaine stares impassively at the reader.

In Toronto this week to do press in advance of the book's release next Tuesday, the metal star, 48, is now a bit more weathered, although he still sports the same wavy orangish hair that drapes down his shoulders, and a T-shirt and jeans that appear to have been with him since the 1980s.

His look and the music, that much remains. But according to Mustaine, everything else has changed.

The book chronicles Mustaine's journey from a neglect-filled childhood, to the dangerous excesses of his rock n' roll lifestyle, to today's more sobering existence as a family man who has found God -- a persona that doesn't quite jive with the typical metal archetype.

"I think in the beginning there were a lot of people who were very angry because they'd lost their guitar player, their singer, their frontman, their Dave Mustaine," he says of the fan backlash after announcing his conversion to Christianity in 2003.

"(But) if you go back and look at all my lyrics now, there's a lot of God in it."

It was a long road of drug and alcohol-fuelled mayhem and tragedy that led Mustaine on a new path.

Before Mustaine fronted Megadeth he played guitar for Metallica, and thrash metal fans are well-versed in his story as one of the founding members of that super group.

But Mustaine was booted from Metallica in the band's early days for his excessive drug and alcohol use, and watched as an outsider as the band took off into superstardom.

Left with nothing and feeling betrayed, Mustaine founded Megadeth. He says the ousting became an "inspiration" and he was fuelled by a need for revenge. In the book, he takes Metallica drummer Lars Ulrich to task for denigrating his contribution to Metallica in its early days.

"Without my songs and my solos -- without my energy -- I don't know that Metallica ever would have become the band that it was," he writes.

Still, Mustaine says he now has "no feud" with the band.

"It was the press that kept that going," he says.

Megadeth soon too rose the ranks in the metal world but Mustaine suffered through many problems, including a near career-ending arm-injury, the near-disintegration of his marriage, and several stints in rehab.

"Heroin was a terrible experience for us," he says of Megadeth's use of the drug. "It was part of my life for 13 years."

It was one of many drugs the band dabbled in and Mustaine says the band's back catalogue offers clues to the progress of their downward spiral.

"You can see where the different types of drugs changed, where the band changed," he says.

"The heroine and the cocaine use, and the debauchery, and the fighting and the theft and stealing and robbing."

Alcoholism also consumed Mustaine, a condition he shared with his estranged father, who died after slipping off a bar stool and hitting his head. With his father on life-support, Mustaine sped to the hospital with a drink in his hand.

"You're going to end up just like him," he sister told him when he arrived.

Mustaine credits religion for saving his life, protecting his family and keeping him going as a member of Megadeth.

"When I got saved it wasn't about getting me saved," he says.

"It was about me getting my life right with God, getting my family out of what looked liked extremely dire straits ... and just making a really good decision for once in my life."

Mustaine wrote his autobiography with the help of journalist Joe Layden. He says the experience was "very cathartic."

Megadeth is currently travelling on the "Canadian Carnage" tour and Mustaine has no plans for stopping.

"I think that I'll be a musician for the rest of my days," he says.