This four-disc set of rarities by the godmother of alt-country is a grab-bag/treasure trove of esoterica that will be manna from heaven for hardcore Emmylou Harris fans, if not the ideal entry point for the uninitiated. It combines previously unreleased tracks with obscure items from dimly lit corners of Harris's catalog. This encompasses collaborations with everyone from Mark Knopfler to Sheryl Crow, cuts from tribute albums, and more. Whether she's breathing new life into Dolly Parton's "Coat of Many Colors," Hank Williams's "Alone and Forsaken," or Townes Van Zandt's "Snowin' on Raton," Emmylou's heartfelt delivery and gorgeous, birdlike timbre stand as a testament to her status as eminence grise in the Americana music scene, a country/folk queen whose musical odds and ends are fully as engaging as her most celebrated works.