A friend to fellow UK folk visionary Nick Drake, John Martyn had his own cult of influence, as this two-disc cover set shows. Drawing on dub and other influences, Martyn took folk-blues into dreamy, uncharted territory, anticipating the roots abstractions of Daniel Lanois and others. Contributors Vetiver, Phil Collins, Vashti Bunyan, and the Cure's Robert Smith make for odd bedfellows. But Martyn's songbook — "May You Never," "Stormbringer," the Drake tribute "Solid Air" — is the star. And with the success of Mumford & Sons (who must've been too busy to contribute), this British folk-pop history lesson couldn't be more timely.

Listen to Robert Smith's "Small Hours":

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“The Everchanging Spectrum of a Lie”

The opener off the Welsh group’s The Big Roar album was an epic one, but the band was worried that track had polarized fans. “The first song is eight minutes long,” Rhydian Dafydd, the Joy Formidable bassist, said. “If you did that in the Seventies people would be, ‘Whatever.’ You do it now, people think, ‘Holy s---!’ Some people think it’s the f---ing greatest track on the entire album, and some people think it’s f---ing boring. It’s that element of needing to challenge people.” The band concluded through the song’s lyrics that love was the “everchanging spectrum of a lie.”