As a progressive bluegrass artist, Alison Krauss came on like a stealth jet. An accomplished fiddler, she really caught the world’s attention as a singer, and even on her earliest solo work you can hear her gently pushing out of the bluegrass corral and into a more poppy, country-derived style. Check out the subtle but clear swing rhythm she applies to “Endless Highway,” and the tricky chord changes on “It’s Over.” She’s clearly destined for stylistically bigger things already.