You have included two songs from the Workbook era on your recent albums (“Trade” on Modulate and “Walls in Time” on the upcoming District Line ). I’d be interested in the process by which you decide to revisit unreleased songs for new projects. —Marc Gerson, the Palisades

It was a matter of which songs I felt most strongly about at the time. “Trade” and “Walls in Time” were good enough songs to finally see the official light of day. With “Trade,” I was working on an electronic piece that was based around the same chord motif. I sensed the similarity and grafted the old words and melody onto the new piece. “Walls in Time” was a song that, by rights, should have been a key piece of Workbook. In 1988, I had written several songs in a confessional narrative style. As Workbook evolved, I favored a similar song over this one; had “Walls in Time” been included, “Sinners and Their Repentances” would have been omitted. With District Line, I lucked into including “Walls in Time” as the closer. The third song on the album is titled “Again and Again”; one of the key refrains in “Walls in Time” is “again and again, day after day.” The two songs lie sympathetically on the circle of fifths, and some of the key chords are the same. A serendipitous musical moment and a perfect thematic fit. —Bob Mould

District Line comes out Feb. 5.