For their fourth album, U2 enlisted the help of producer Brian Eno and his protégé Daniel Lanois, an engineering team noted for their experimental and ambient recording styles.The overall moodiness here makes for an entrancing listen of a group about to be catapulted into the stratosphere of superstardom. In 2009, the band issued this 25th Anniversary Edition that further expands on what is now clearly one of their most important and transitional albums. Recorded at Slane Castle, Ireland, where the album’s initial sessions took place, outtakes such as the wordless “Yoshino Blossom” and “Disappearing Act,” a track from 1983 the band recently finished up, sustain the album’s moody pull. Live cuts from the Wide Awake In America EP (“A Sort of Homecoming,” “Bad”) showcase the band’s continued peerless live authority. Atmospheric b-sides such as the instrumental “Boomerang I,” the Joy Division-derived “11 O’Clock Tick Tock” and the wordless “Sixty Seconds In Kingdom Come,” two remixes of “Wire” and an extended mix of “Pride (In the Name of Love)” are among the many highlights.