Don’t ask, “What’s the single?” Among its many accomplishments, this collaboration is a great argument on behalf of a complete, sequenced set. The two singer-songwriters — helped along with superb production from Jim James — build their case gently. With a mostly modest variety of instrumentation (in sometimes eccentric arrangements), the three main participants speak to life’s simple gifts and how these might disappear, in what amounts to a monumental theft from our children. Meanwhile, many of the tunes and lyrics play off of Appalachian cultural traditions, sans any twangy cliché. Once you also lock into recurring lyrical motifs, it’ll be clear this is a unique and reverberating statement of contempt for mountaintop removal mining. They’ve made a work of art that’s idiosyncratic in the best sense. One odd inclusion is “Only a Song,” which edges toward coy manipulation. But it’s got a fine melody, and they had to approach within spitting distance of an anthem sometime here, or the set might not wake up the ears that need to hear. Ben Sollee and Daniel Martin Moore perform Friday, Feb. 26 at The Brown Theatre. Showtime is 8:30 p.m. Tickets are $25.