"He found an example within the field of music. He said, imagine that you walk down a street past, say, a car where someone has the radio on and it plays a tune you've never heard before but which is so fantastically good it just stops you in your tracks. You listen until it's done. Days later you remember exactly what that street looked like when you heard that music. You remember what was in the store window you stood in front of. You remember what the colors of the cars in the street were, where the clouds were in the sky above the buildings across the street, and it all comes back so vividly you wonder what song they were playing, and so you wait until you hear it again. If it's that good you'll hear it again because other people will have heard it too and have had the same feelings and that will make it popular. One day it comes on the radio again and you get the same feeling again and you catch the name and you rush down the street to the record store and buy it and can hardly wait until you can get it home and play it."(From Robert Pirsig's 'Lila')
See also here. The Martyn Joseph website is here.