Came the 'fifties and the bands gave way to a beat that was, while ""musically Neanderthal,"" irresistible. But according to the articles assembled here, the age of rock did not dawn until it found its first prophet, Dylan, and its own sacraments in electronic sound. And Nat Hentoff says you better tune in man because of its revolutionary and even evolutionary effects. And H. F. Mooney says it's changed the psychology of a generation. Other pieces resurrect The Grateful Dead, The Beatles, The Stones and ""That Great White Beautiful Bitch,"" Janis Joplan. There's a wonderful portrait of Dylan putting on and putting down an inane reporter; an intimate and intimidating look at the new phenomenon known as ""groupies,"" who don't stop at autographs; and an extremely neat dissection of why ""Rock Lyrics are Poetry (Maybe)."" Also scenes with The Doors and at the Fillmores and there's Jon Landau on The Motown Sound and what's up down in Nashville. A rock-it-to-'em collection that is interesting and occasionally inspired. And for the over-thirties there's even a day with the Pelvis (who now rods his motorcycle around his swimming pool). So much for the old Hound Dog.