Weiner's summary of The Byrds as ""one of the most remarkable stories of consistent failure in the annals of modern pop"" is of course hyperbole, a way of bestowing glamour on a group that never really achieved it. To be sure they have been more ""artistically important"" than commercially successful though Weiner is at a loss to explain exactly why. Since The Byrds were never very good in live performances, Weiner follows them album-by-album, continually marveling at just how fine they are. Part of their interest comes from a checkered career and frequent changes of personnel; they're ""a living textbook in group breakdown"" with Roger McGuinn, founder and lead vocalist, the only member of the original group left. The rest comes from such tunes as Eight Miles High, Space Odyssey, Jesus is Just Alright With Me and Mr. Tambourine Man plus that slick, world-weary style which in eight years has carried them from folk rock to space rock to acid rock to country rock. Just what is the secret of their longevity? McGuinn's cynical opportunism? Technical excellence? Their strange melding of the rural past and the technological future with its overtones of down home revival meetings and sci/fi fantasies? Weiner doesn't say because he's not so sure himself. Their musical restlessness has been called ""motion for its own sake,"" easier to recap than interpret, and that's all Weiner does.