When the Can studio in Weilerswist was sold to the German Rock N Pop Museum, they bought everything, including the army mattresses that covered the walls for sound protection, and relocated it to Gronau. Whilst dismantling the studio, master tapes were found and stored in the Spoon archive. With barely legible labeling, no one was sure what was on these until Irmin Schmidt and long time collaborator Jono Podmore started to go through over 30 hours of music. What they found was years of archived material, not outtakes, but rather tracks which had been shelved for a variety of reasons – soundtracks to films that were never released and tracks that didn't make it onto the final versions of albums due to space. Irmin Schmidt explains "Obviously the tapes weren't really lost, but were left in the cupboards of the studio archives for so long everybody just forgot about them. Everybody except Hildegard [Schmidt, Irmin's wife], who watches over Can and its work like the dragon over the gold of the Nibelungen and doesn't allow forgetting."
The final cut of tracks, dating from 1968–1977, features studio material recorded at Schloss Nörvenich and Can Studio, Weilerswist with the Can line up of Holger Czukay on bass, Michael Karoli on guitars, Jaki Liebezeit on drums and Irmin Schmidt on keyboards, and on most tracks, vocals from Malcolm Mooney or Damo Suzuki.