It can be argued the surest proof of The Beatles' artistic genius is to be found in the quality of their B-sides. Between 1962 and '70, the iconic quartet released approximately two dozen singles. On no less than half of them, the flipside is as equally engaging as the tune occupying the side A. This is an utterly mind-blowing achievement. The Rolling Stones and The Beach Boys released some truly fantastic B-sides throughout the '60s, from the former's "Ruby Tuesday" to the latter's "Don't Worry Baby." Yet neither outfit, however awesome, came close to rivaling The Beatles' consistently high-level output and creativity. "Revolution," "I Saw Her Standing There," "I Am the Walrus," "Eleanor Rigby," "Don't Let Me Down" and "Strawberry Fields Forever" were released as B-sides, and rank among the greatest rock songs of all time. But even The Beatles' less celebrated flipsides stand as dazzling sonic artifacts. "Rain," the B-side to 1966's "Paperback Writer," is a droning, psychedelic masterpiece. Paul McCartney's "Things We Said Today," which backed A Hard Day's Night" on the U.K. single, is one of the early Beatles' most sophisticated and emotionally compelling songs. To hear all these fabulous B-sides and more, just press play.