My God, has it only been three years since Blood Mountain? Maybe it's simply due to the vast changes I've gone through as a person since then (and so I should have: I was fourteen at the time!) but that record almost seems to belong to a different time altogether, and Leviathan seems almost pre-historic. Mastodon are a band I've been aware of almost since the very beginning (well, Remission, anyway) and their particular brand of primeval sludge was, if not solely responsible for getting me into extreme metal, certainly a deciding factor. Since then of course they've matured quite a bit. Blood Mountain was their breakthrough release, getting more melodic and progressive while never losing their handle on the berserker heaviness that made people sit up and notice. Tours with metallic juggernauts such as Slayer, Metallica and Tool followed, and Mastodon came off the back of that album looking like a band who could take on the world. And so, perhaps even more so than Blood Mountain, this is the most important album the Atlanta foursome have ever had to make.

And so it's so surprising, then, that Mastodon have taken such a gamble with Crack The Skye. This is a more refined Mastodon, although the familiar sludge is still there, it's evolved into something quite different. Fans still longing for a return to the brutality of Remission may be dismayed, but those of us who viewed the leap forward that was Blood Mountain as a change for the better are in for a treat here.The songs are more complex than ever, with even lead-off single Divinations being a note-dense tech-metal workout. The record opens not with full-throttle roar of The Wolf Is Loose or Blood And Thunder, but with the warm glow of Oblivion, basking in acid-fried grooves, and soaring vocals not only from usual suspects Troy Sanders and Brent Hinds, but also drummer/lyricist Brann Dailor taking lead vocals here for the first time (and I must say he does a fantastic job). And then, of course, there are the two 10+ epics, The Czar and The Last Baron being the most riff-stuffed, complex things the band have cut to tape yet. Nothing here could be described as simple though, Divinations being the closest we ever get to a tightly structured-song.

Everything about Crack The Skye signifies a band who have broken enough eardrums around the world to have proved themselves, and now want to show the world that there are more strings to their bow, that they're capable of subtlety and nuance (If their past works hadn't proved that to you already, of course). The most notable change here is most definitely the vocals. The guttural roars of old have generally been replaced with clean singing, and the band have bettered themselves once again. Both Hinds and Sanders sound richer and better than ever, hopefully without the use of studio trickery (I saw them back in the Blood Mountain days, and I'm afraid Brent sounded awful live). Perhaps even more notably, the words they're actually singing flow better and are more meaningful than ever. Rather than stringing fairly nonsensical phrases together to narrate some kind of concept, Dailor's genuinely dug deep here, trying to tell a proper story (which I'm afraid is every bit as insane as Blood Mountain was, taking in paraplegics, wormholes and Rasputin). Crack The Skye happens to be the most starkly personal song the band have written, dealing openly with the suicide of Brann's sister, while somehow weaving it seamlessly into the more fantastical concepts that abound elsewhere. It's also worth mentioning the keyboard work here, which adds a new layer of melody to the music without ever detracting from the heaviness. The wonderfully 70s organ tones are well-chosen, a sure sign of the classic and progressive rock influence guitarist Brent Hinds has been trying to work into their music.

Only time can truly judge Crack The Skye, but from here it seems Mastodon have delivered their third world beater in a row. While they've been at the forefront of metal for the past five years, it's here that they've truly shown they have what it takes to join the pantheon of metal gods. Crack The Skye crackles with energy and ambition through every second of its fifty minutes, every song here having “future classic” stamped all over it. Mind, I thought that with Blood Mountain, and yet it's really quite shocking how, well, small it seems in comparison with this latest opus (without denying its brilliance). I for one can't wait to see how Mastodon plan to put this one in the shade, and if you'll excuse the rather tacky pun, the Skye's the limit for the band.