Is pop music serious? AI has helped The Beatles regroup one last time. Critics hail the "powerful" reunion of Lennon and McCartney on Now and Then. But does the music matter?
The cheerful moptops that changed our culture
Fab four: The Beatles are the most successful act in the history of the US Billboard charts. Glossary
Catharsis - Originally used by the Ancient Greek philosopher Aristotle to explain the power of art to dispel strong negative emotions. The term is used in psychotherapy to describe how patients can overcome difficulties by expressing and facing their fears.
Capitalism - A form of economy characterised by private property and competition between companies.
Soviet - Relating to the Soviet Union, a powerful group of communist republics, the biggest being Russia, that existed from 1922 to 1991.
Communism - The system of organising society so that all property is owned by the community and everyone receives things according to their needs.