Waylon Jennings’ final studio album is a remarkable achievement. With its swampy groove, “Closing In On the Fire” is a song of carnal love, but the title also refers to a life nearing its end. “Easy Money,” “The Blues Don’t Care” and “I Know About Me, Don’t Know About You” (with Travis Tritt) echo the rugged country-rock of Jennings’ heyday, as if to prove he still had the fire. Several songs — especially the rollicking “Best Friends of Mine,” the paternal “Just Watch Your Mama and Me” and the sweet “Be Mine”— feel like concluding, faithful statements on the most essential aspects of Waylon’s life. The cross-generational guest list is an affirmation of Waylon’s influence and reputation. Younger performers Sheryl Crow and Mark Knopfler appear on “She’s Too Good for Me” (written by Sting), while Nashville legend Carl Smith duets on “Untitled Waltz.” Most importantly, Closing In On the Fire sounds vital. Jennings is in fine voice, his commanding baritone undiminished even after forty years of performing. There is boldness in the material and hunger in the performances. Jennings may have been close to the end, but he invests the music with a rookie’s purpose.