This collection, assembled in honor of Amnesty International's 50th birthday, is stuffed with 80 artists, from Pete Seeger (folk-music deity, b. 1919) to Miley Cyrus (hot mess, b. 1992). Revelation and humor are in as short supply as hip-hop; instead, you get a good catchall for a great cause, with head-scratchers and surprises side by side (Miley turns out to be both). Most often those who underplay their covers play it best: Pete Townshend's fingerpicked "Corrina, Corrina" captures the grace and grief of Dylan's best love songs; Ke$ha treats "Don’t Think Twice" as an acting-class monologue and earns a callback; Lucinda Williams mumbles the mysticism of "Tryin' to Get to Heaven" until it feels like barroom banter; My Morning Jacket turn "You’re a Big Girl Now" into a paper kite floating in space. Not everything is a keeper – My Chemical Romance can't find their way out of "Desolation Row," and instead of Gaga painting the daytime black, we get her producer RedOne plodding through "Knockin’ on Heaven's Door." In the end, Chimes of Freedom is like one of those carnival songs Dylan used to knock off in a single take of amphetamine-fueled laughter and tears: You'll lose track of the winners and losers as the flood rolls on, and the next time you take the trip, you'll notice the scenery has completely changed. That may be the most fitting tribute of all.

Listen to "Don't Think Twice":

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