Crack the Skye is the fourth studio album by American heavy metal band Mastodon, released on March 24, 2009, through Reprise, Sire and Relapse Records.

Crack the Skye is the first studio album to feature drummer Brann Dailor as the band's third lead vocalist.

"[14] When asked in multiple interviews Dailor said the record would tell a story dealing variously with the art aesthetics of Tsarist Russia, astral travel, out of body experiences and Stephen Hawking's theories on wormholes.

He goes out of his body, into outer space and a bit like Icarus, he goes too close to the sun, burning off the golden umbilical cord that is attached to his solar plexus.

[17] My sister passed away when I was a teenager and it was awful, and there's no better way to pay tribute to a lost loved one than having an opportunity to be in a group with my friends and we make art together.

I took it really seriously and I emailed with Brann's Dad a couple of times and just talked to him about Skye, and then he sent me a photograph of her actually, and I sat there and looked at that photograph of her and just kinda meditated on her and on all of the situation, and the family and then actually set all that shit up in the studio and recorded the song with her picture there, and I just really tried to do it as real as I felt I could.Paul Romano, who had done all of Mastodon's album artwork to that point,[citation needed] created the art for Crack the Skye.

[citation needed] A "hidden" picture of Brann Dailor's sister, Skye, can be seen on both sides of the tunnel book as well.

[19] Amongst the positive reviews received from critics was Total Guitar's Nick Cracknell who awarded the album a 5/5 rating, describing it as "even more ambitious in scope and sound than 2006's Blood Mountain.

Embracing elements of prog and country, but above all classic rock, Hinds and Kelliher literally add new dimensions to the band's ever-expanding sound."

Decibel, who named Blood Mountain as their number 1 album of 2006, gave Crack the Skye a 7/10 rating as reviewer Joe Gross responded that "Crack is clearly designed as a grower, not a shower, the sound of a band that grew tired of people not responding to their ground game, so they put the ball in the air.

Reviewer Nate Chinen of The New York Times noted the album's "ambitious vision and vivid execution".

[39] All tracks are written by Mastodon, except "Crack the Skye" (additional lyrics by Scott Kelly)‡ Sales+streaming figures based on certification alone.