MASTODON's Brann Dailor (drums) and Troy Sanders (bass, vocals) spoke to the British web site The Quietus his week about the concept behind their fourth album, "Crack The Skye", due out on Reprise early next year. An excerpt from the chat follows below.

The Quietus: You've been quite vocal in the press saying that it isn't a concept album about Rasputin [Russian mystic Grigori Yefimovich Rasputin].

Brann Dailor: "No one wants to go head to head with BONEY M…"

Troy Sanders: "Exactly!"

The Quietus: Is there a theme or a concept?

Brann Dailor: "Yeah, there's a story which goes from start to end. And there is Tsarist Russia in there and that was picked because ever since the first record we've wanted to do something about this period and their art aesthetics, with the black lacquer boxes and that look was something we were going for. From there, you take elements of that, and it's multi-dimensional and it goes into outer space and it's about the ether and deals with astral travel, out-of-body experiences and deals with Stephen Hawking's theories on wormholes. But I think one of the cool things about our band is that we will leave it ambiguously for the listener to dive into the lyrics themselves and maybe come to their own conclusions and form a little movie that plays in their heads."

The Quietus: This is what's great about heavy metal — you would never get an OASIS or ARCTIC MONKEYS album about something like this. Just an album about having a top laugh with your mates.

Brann Dailor: "It's fun for us to research all that stuff and get it all in there and make it as nuts and as far out as we can. I feel like we've worked hard on the lyrics, that they're more meaningful and they're going to be able to get more out of them this time. I mean, it's all metaphors for stuff that goes on in your everyday life, like being away from home and missing your lady or whatever, but it's not so literal. You tell it through a totally different mindset. So it becomes that we're not going on tour but we're going into outer space. But that's how you feel sometimes. You're on tour and you can't get Internet and your mobile doesn't work and you haven't talked to your wife for a week and you feel lost… That's what it's like sometimes."

The Quietus: A good metaphor is a good metaphor and should be celebrated. I for one don't want to hear about how much it sucks being a rock star or how it's not that good being on tour.

Both: "Exactly."

Brann Dailor: "There are ways you can explain those feelings differently through lyrics."

Read more from The Quietus.