Acquired wisdom has always put Sgt. Pepper at the head of the class, but it was Revolver that truly signaled The Beatles' sea change from a functional band to a studio-based ensemble. These changes began before Rubber Soul but came to fruition on Revolver, which took an astonishing 300 hours to produce, far more than any rock record before it. The making of Revolver--hunkered down in Abbey Road with George Martin--is...