Singer-songwriter Conor Oberst's debut album for Nonesuch Records, Upside Down Mountain, is, as its title implies, a study in contrasts, a glance up to the heavens and a glimpse into the abyss. "There's a certain solitude to this record," Oberst admits, and themes of loneliness, dislocation, and regret repeatedly surface. Yet its making was far from solitary, as Oberst gathered friends old and new for the recording, including producer Jonathan Wilson, engineer Andy LeMaster, bassist Macey Taylor, multi-instrumentalist Blake Mills, and the Swedish sibling folk-rock vocal duo First Aid Kit. On hushed ballads like "Double Life" and "Artifact #1," the instrumentation is often stripped down to voices, guitar, and ghostly keyboard; those songs are juxtaposed with tracks like "Governor's Ball," which sports practically buoyant horn charts, and "Kick," which is exuberant rock and roll. A squall of electric guitar at the end of "Zigzagging Toward the Light" segues into a Johnny Cash shuffle on "Hundreds of Ways." The overall warmth of the sound tempers the starkness of the stories being told and Oberst renders his carefully detailed lyrics with an easy intimacy, the still youthful quaver in his voice poignantly underscoring the rueful, decidedly mature words.