"Mostly I hear experimentation, trial and error." Gillian Welch is recalling her and partner Dave Rawling's 1996 Americana landmark debut, Revival. Her modesty is unwarranted. This is a revealing 21-track collection of outtakes, alternate versions, mixes and demos, some equal, if not superior, to the versions that made the album.

These dark, mostly stripped-back tracks, including eight songs previously unreleased, expand our understanding of that signature recording, not least the road to her true voice. The gossamer Paper Wings (alternate mix) floats in pedal steel heaven, while the home demo of Tear My Stillhouse Down crackles with self-loathing, anger and guilt.

Red Clay Halo, later to appear on Time (the Revelator), also didn't make it. It was in good company; Dry Town, cut from Johnny Cash's cloth, was another. Warts and all reissues can test the most loyal, but these gems, albeit flawed, simply fascinate. gillianwelch.com