"The Sunset Sound mix of 'Stairway to Heaven' was actually mixed at Sunset Sound in L.A. in advance of the version that everybody knows," says Jimmy Page. "I think it's a really good embodiment of everything that's on there. It's a guitar mix, really."

Released in November 1971, the album - which is officially untitled - defined the sound of rock music for a generation with ubiquitous anthems such as "Stairway To Heaven", "Rock And Roll", "Black Dog" and "When The Levee Breaks". The album was inducted into the Grammy Hall Of Fame in 1999, has been certified 23x platinum by the RIAA.

The "Led Zeppelin IV" deluxe edition includes unreleased versions of every song heard on the original album including alternate mixes of "Misty Mountain Hop" and "Four Sticks", mixes of "The Battle Of Evermore" and "Going To California" heavy with guitar and mandolin, and the fabled, alternate version "Stairway To Heaven", mixed at the Sunset Sound Studio in Los Angeles which lets fans hear one of the most revered songs of all time as they have never heard it before.