It's that time of year again: another Drive-By Truckers album, another wad of lyrically incisive, liberally rocking Southern-fried swamp-rock. Last year's Decoration Day saw the Truckers selling their local morality tales to an increasingly universal audience hungry for "authenticity" accented by uplift and hope. The Dirty South, as the title suggests, is meaner and dirtier, and if it doesn't attract the same tourists as Decoration Day, you only have to listen to a tune like the agonizing "Puttin' People on the Moon," in which singer/guitarist Patterson Hood inhabits a guy who gets downsized, starts selling drugs, loses his wife to cancer and ends up working at Wal-Mart, to hear why. Fans, though, will find a feast: second singer/guitarist Mike Cooley's chiming music-biz lament "Carl Perkins' Cadillac," third singer/guitarist Jason Isbell's driving blue-collar lament "The Day John Henry Died," Hood's delicate World War II lament "The Sands of Iwo Jima." And, throughout, the band's singular musicality, which somehow leavens a post-Skynyrd three-guitar roar with little shards of sweetness and light--shards that don't necessarily redeem these hard-luck characters but that give their stories a devastating humanism, the knowledge that whatever's happened didn't have to.