If rock music is all about transience, how can a song born decades ago still rev up the engines of romance? “Tangled Up in Blue”, for instance, is a tale of fading love, but the power and significance of the song itself is timeless. Rock ‘n’ roll is often an expression of youth or youth’s passing, but when music (or any art) endures, its magnetism is only amplified with the passage of years. For that reason, and because the best songs are usually pinned by the listener to some quintessential moment, the classics become classic. Passion is a fleeting feeling, but the best art will evoke that feeling with every exposure.