Jessie Baylin has been on the periphery of fame for more than half her life. At 19, she had the “it” factor as a singer-songwriter in L.A. A publishing deal with Sony, an audience with famous musicians like Justin Timberlake and John Mayer. At 22, she was engaged to a drummer, Nathan Followill, who she met at a music festival. At 25, they were married the same year his band, Kings of Leon, were conquering arenas around the world on the strength of hits like “Sex on Fire” and “Use Somebody.” In 2018, Baylin’s primary songwriting partner and producer Richard Swift died, which was a blow to the Nashville music community, as Swift was one of those peripatetic forces. He had ties to the Black Keys, the Arcs, the Shins, and more. But for Baylin, Swift was her musical lifeline, the person w...