by Rick Anderson As a founding member of the legendary German avant-garde ensemble Can, Holger Czukay is widely recognized as a founding father of experimental rock'n' roll. After his acrimonious split from the band, Czukay swore he'd never play live again. But the sounds of jungle, techno and trip hop rekindled his interest in the club scene, so when Dr. Walker (of Air Liquide) invited Czukay to join him onstage during an underground party in Cologne, Germany, he was ready. This impromptu duo performance led to a number of more formal engagements, three of which are partially documented on these two discs. Disc 1 features three tracks from the duo's gig at the Liquid Sky club in Cologne. After a long, freeform preface, "Silent Planes" settles into a trance-inducing midtempo groove and stays there for most of the track's 19 minutes. "Liquid Skies" is more aggressive and also more varied in texture. Czukay makes great use of a radio receiver on "Twilight," from the duo's performance at the Great American Music Hall in San Francisco, while "Backup Dream" is funkier but also more sinister. Disc 2 continues the San Francisco material with the surprisingly abrasive "Monks, Whales and Moonbeams (Over California)" and "Anything but the Jungle." The last two tracks, the 24-minute-long "Dawn Across the Street" and a lovely piece of multicultural big beat entitled "Full Circle," come from a gig in Minneapolis. Excellent.