The essential tunes by the Sixties' first true supergroup a cynic would be tempted to subtitle this collection And Definitely Not Young. But before CSNY, there was only CSN — the original late-Sixties harmonic convergence, often dysfunctional, more often magical. Composed of former Byrd David Crosby, Buffalo Springfield's Stephen Stills and runaway Holly Graham Nash, CSN were the first supergroup worthy of the tag, thanks to early showcases like "Suite: Judy Blue Eyes" and "Marrakesh Express." Where earlier groups such as the Everly Brothers and the Beach Boys offered brotherly blends of harmony, CSN introduced a revolutionary chemistry of varied voices and songwriting styles. Neil Young gave the group an extra explosiveness, but this set spotlights CSN's core power and proves that their promise wasn't wasted along the way.

“1999”

“I don’t consider myself a great poet,” Prince told Rolling Stone. “I just know I’m here to say what’s on my mind.” In the case of the apocalyptic party anthem “1999,” he was worried about then-president Ronald Reagan’s foreign policies. The song’s melody is based on a riff borrowed from the Mamas and Papas’ “Monday, Monday,” and Prince originally envisioned the first verse with three-part harmony but later split the vocals between himself and members of the Revolution. Because Warner Bros., with whom Prince was locked in a contractual battle, owned the original’s masters, Prince rerecorded the song and appropriately released that version in 1999.