Cut a decade apart, mostly without any collaborators, these two albums feel like outtake sets, in the best possible way: music that chases any crazy idea down a dark alley. Released three weeks before Let It Be in 1970, McCartney announced Paul's love for his wife and the breakup of the Beatles. What makes it so touching is how much it tries to re-create the Fabs. McCartney played every instrument: Ringo-101 drums ("Every Night"), Harrison-ish slide ("Man We Was Lonely"), Lennon blues-rock guitar ("Oo-You"). The masterwork is "Maybe I'm Amazed"; other songs make you wonder what they might've become with his mates around.

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1980's McCartney II, made while Wings were on hiatus, was another purely solo effort. "Waterfalls" is a Rhodes-driven ballad that would make a great Adele cover, but what's striking is a kooky experimentalism — see the leering, Kraftwerk-y "Temporary Secretary" — that foreshadows the current era of the laptop dance-pop auteur. Both McCartney and II come in deluxe editions, appended with DVDs full of home movies and other ephemera; the best bonus track is "Suicide," a music-hall outtake that collapses under its titular metaphor. For someone who could write perfect pop songs with the effort it takes most folks to assemble a sandwich, these freewheeling records must've been fun to make. They sound like it.

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“I'm Yours”

Jason Mraz re-emerged after his disappointing second album with this lead single, a Jack Johnson-esque ditty about giving yourself fully to someone else. The success of the reggae-tinged song (it earned two Grammy nods and a spot on the Billboard singles chart for well over a year) was something the folk-pop singer never predicted when he wrote it in 15 minutes at home. "I played a happy-hippie chord progression that would probably work without 50 different Bob Marley songs," he told Rolling Stone. "I thought, 'It's too novelty. This is a nursery rhyme,'" concluding that "you can never guess what's gonna be a hit."