Twenty years ago, Bono described Achtung Baby as "the sound of four men chopping down The Joshua Tree" while Jon Pareles of The New York Times wrote that "stripped-down and defying its old formulas, U2 has given itself a fighting chance for the 1990's." The album won a Grammy Award for Best Rock Performance and became one of the most significant records of the nineties and of U2's career.

To mark twenty years since its 1991 release, an anniversary edition of U2's Achtung Baby is due on November 1, 2011, in the United States (internationally, October 31, 2011).

Recorded over six months at Hansa Studio in Berlin and Windmill Lane in Dublin, Achtung Baby is U2's seventh studio album. Produced by longtime U2 collaborators, Daniel Lanois and Brian Eno with Steve Lillywhite, Achtung Baby was engineered by Flood and led by "The Fly." The album spawned four other singles: "Mysterious Ways," "One," "Even Better Than The Real Thing" and "Who's Gonna Ride Your Wild Horses."

The Achtung Baby archives have unearthed some previously unreleased songs from the recording sessions. With a raft of unreleased material, video, remixes, b-sides and documentary footage discovered, a full album of demo and early versions of the final 1991 tracklisting has also been revealed. Five physical editions including vinyl, CD, DVD and digital options will be made available.

Earlier this year U2 returned to Hansa Studio in Berlin to discuss Achtung Baby in From The Sky Down, directed by Academy Award-winning director Davis Guggenheim (Waiting for Superman, An Inconvenient Truth). The film has been selected to open the Toronto International Film Festival on September 8 and will be included in the anniversary edition.

Five physical editions of the anniversary edition of Achtung Baby will be available alongside digital only editions.

1. A limited, numbered Uber Deluxe Edition is a magnetic puzzle tiled box which will contain: 6 CDs including the original Achtung Baby album, the follow-up album, Zooropa, B-sides, remixes and re-workings of previously unheard material recorded during the Achtung Baby sessions. 4 DVDs including 'From The Sky Down', 'Zoo TV:Live From Sydney', all the videos from Achtung Baby plus bonus material. There will also be the Achtung Baby double vinyl album plus 5 clear 7" vinyl singles in their original sleeves, 16 art prints taken from the original album sleeve, an 84-page hardback book, a copy of Propaganda magazine, 4 badges, a sticker sheet, and a pair of Bono's trademark 'The Fly' sunglasses.

2. The Super Deluxe Edition will contain the 6CDs and 4 DVDs, in addition to a 92 page hardback book and 16 art prints in a wallet.

3. The Vinyl Box Set is a limited release containing 4 LPs, two of which are pressed on translucent blue vinyl containing remixes and B-sides. The box includes a 16 page booklet.

4. The Deluxe Edition is a 2xCD set containing the reissue of the original album plus B-sides and rarities.

5. The Standard CD is the original album.