The Beatles transcend time, geography, demographics and personal taste

As the anniversary of John Lennon's murder approaches, we are reminded again that the band's magic never disappears

My friend Michael is a musicologist whose speciality is Johann Sebastian Bach. An author and lecturer, he speaks to erudite groups in many countries about, for example, Bach's Mass in B minor.

Michael doesn't think much of most popular music.

Margaret Sullivan is a Guardian US columnist