The mid-'70s were a time of reckoning. It was also an era of paradoxes, of record making and record breaking, of sold-out shows, and, in the minds of some, sell-out artists. Critics, who once exalted the shamanic characteristics of rock...

From its artful beginnings (Syd Barrett-era Pink Floyd, the Mothers of Invention, and those progressive forebearers, the Sgt. Pepper-era Beatles), through the towering guitar solos, monumental synthesizer banks, and mind-boggling special...