Most of the power in any country song comes from the imagery in its lyrics. And that's why Southeastern, the third solo album by former Drive-By Trucker Jason Isbell, is a very good album: It's filled with scenes you can easily picture, and lines that arrive with the rare, devastating heft of Truth. The way he carefully unfurls the cancer story of "Elephant": "She said, 'Andy, you crack me up'/Seagram's in a coffee cup/Sharecropper eyes, and the hair almost gone." The way he indicts his lonely self on "Traveling Alone": "So high, the street girls wouldn't take my pay/She said come see me on a better day, and she just danced away." The entirety of "Live Oak," a pre-Civil War tale of a murderer softened by love: "We'd robbed a great-lakes freighter/Killed a couple men aboard/When I told her, her eyes flickered like/The sharp steel of a sword." Isbell, now 34, committed a few lifetimes' worth of hell-raising as a Trucker and a solo artist before recently getting sober. Whether it's the onset of clarity, his summer marriage to collaborator and tour opener Amanda Shires, or something else, his songwriting has hit a new level of potency of late.