For anyone whose life has been spent in thrall to rock ‘n’ roll, it’s no news that-- heard at the right time, the right age, in the right place--a song, an album, even a line can sound as if the secrets of the universe are opening before you. Rock ‘n’ roll is the great populist art form. Its great contradiction is that it can also draw lines through generations, friendships, even our own lives. And so, while those secrets burst forth to us as if uttered by some cosmic whistleblower, to others they can sound like gibberish, like an obscenity, like nothing. I can’t tell you what a-wop-bop-a-loo-bop-a-lop-bam-boom means, or what goo goo g’joob means, or why the cheesy organ in “Sweet Pea” has the effect a siren’s song did on mariners, or why the sudden rough downstroke that ends Lindsay Buckingham’s guitar solo in “Go Your Own Way” sounds like a man emerging, panting, from a fever. The secret club at the heart of this populist art is made up of people for whom those words, those sounds, those inflections (“I’ve thrown away my nights/wasted all my days/over you-oo-oo uh-oh”) were heard as coded transmissions from the underground. This music, almost always thought of as aggressive, often chooses to whisper its meanings, confident they will find their intended targets and be understood. When the Beatles asked “Do You Want to Know a Secret?” they could have been looking for the fans ready to hear the unimagined music still to come.