for more than 40 years , its lyrics have been an enigma wrapped in an eight-and-a-half minute long rock 'n' roll puzzle .
argued over by generations of geeky fans , deciphered and re-deciphered by code-breaking rock nerds and considered to be poetic reflections on mid-20th century u.s. social history by even groovier academics , it 's called american pie .
and this week its lyrics , hand-written in 1971 by a young folk singer called don mclean .