Folk "supergroup" Bonny Light Horseman, born out of a chance collaboration at the 2015 Eau Claire festival, is a fascinating standalone project of three musicians — Anaïs Mitchell (Hadestown), Eric Johnson (Fruit Bats), and Josh Kaufman (Bob Weir, Hiss Golden Messenger) —  each with a distinguished track record, uniting over a shared love of folk music in the Anglo-American traditions.

Of the three, singer-songwriter Anaïs Mitchell offers the deepest credentials in folk music, from her 2013 record of the Child Ballads, the anthology of Scots-English traditional folksongs, and her Tony Award-winning adaptation of mythology in Hadestown. Johnson provides his extraordinary facility with banjo and guitar and his effortless tenor. In contrast, Kaufman, the quietest member of the trio, provides much of the texture of Bonny Light Horseman's refracted folk songs, on steel guitar and other instrumentation…