Shawn Colvin and Steve Earle both remember the night they met. It was nearly 30 years ago, and Colvin had been invited to open a solo acoustic performance by Earle at the Iron Horse in Northampton, MA. Though their interactions that night were limited to some cursory dressing room pleasantries, each left more of an impression on the other than they may have realized at the time. “I was knocked out with her,” says Earle. “She was a real life folk singer.” “I was a big fan—still am—and I was thrilled I got to meet him,” reflects Colvin. The duo’s collaboration began two years ago with a phone call from Colvin, who had just wrapped up a joint tour with Mary Chapin Carpenter and found the experience offered a different set of artistic rewards from her typical solo touring.