After a now-familiar teaser campaign involving cryptic posters and a blurry video, Radiohead have announced details of the forthcoming 20th anniversary edition of their groundbreaking 1997 album “OK Computer,” which will be part of a larger package titled “OKNOTOK.”

“Rescued from defunct formats, prised from dark cupboards and brought to light after two decades in cold storage… OKNOTOK will be issued June 23rd on XL Recordings, coinciding (roughly) with the original 1997 release date(s) of Radiohead’s landmark third album OK COMPUTER,” the press release reads.

The collection will feature the original 12-track “OK Computer” album, eight B-sides and the previously unreleased original studio recordings of three tracks: “I Promise,” “Lift,” and  “Man Of War,” which have circulated in various forms on bootlegs for many years. It will be available in digital, double CD, and triple 180g LP formats via the group’s recent catalog deal with XL. The album was originally released on Capitol/EMI.

In typically wry language, the press release continues: “The OKNOTOK BOXED EDITION will ship July, featuring a black box emblazoned with a dark image of a burned copy of ‘OK Computer’ containing three heavyweight 180 gram black 12″ vinyl records and a hardcover book containing more than thirty artworks (many of which have never been seen before) and full lyrics to all the tracks (except the ones that haven’t really got any lyrics).

“Under this weighty tome are yet more surprises: a notebook containing 104 pages from Thom Yorke’s library of scrawled notes of the time, a sketchbook containing 48 pages of Donwood and Tchock’s ‘preparatory work’ and a C90 cassette mix tape compiled by the band, taken from ‘OK Computer’ session archives and demo tapes.”

Containing the singles “Paranoid Android,” “No Surprises” and “Karma Police,”  the album, Radiohead’s third, earned the group its first U.K. No. 1 album and its first Album of the Year Grammy nomination. Coming after the global success of their 1993 “Creep” single and ecstatically reviewed 1994 album “The Bends” — which contained “Fake Plastic Trees” and “High and Dry,” still fan favorites — “OK Computer” marked a turn into darker and more aggressive territory. Yet the album and the year-long tour that followed turned the group into a major, truly global act. It also completely changed them: The exhausting and often ridiculous demands of stardom, depicted in the 1998 documentary video “Meeting People Is Easy,” led the group to reject the course they were on and veer into even darker and more electronic music on their 2000 and 2001 follow-up albums, “Kid A” and “Amnesiac.” Since that time the group has followed a delicate balancing act of rejecting the trappings of rock music and stardom in general, while remaining one of the world’s biggest acts.

The band recently completed a brief U.S. tour and will trek across Europe beginning in June, including a headlining appearance at England’s Glastonbury Festival on June 23.