Undeniably, Sgt. Pepper is an experimental classic, a triumph of influence. But I don’t consider it even the best Beatles album; that’s Rubber Soul or Revolver. On the Sgt. Pepper album, however, is “A Day in the Life,” which is my idea of a perfect song. It is the epitome of The Beatles’ master building, of fitting stone upon stone, each section troweled together with such ingenuity and care that upon completion the whole thing feels seamless, a structure not built at all, but a whole that simply was.