Italo Calvino's 14 Definitions of What Makes a Classic

The list, care of Brain Droppings.

From said list...

1. The classics are books which exercise a particular influence, both when they imprint themselves on our imagination as unforgettable, and when they hide in the layers of memory disguised as the individual's or the collective unconscious.
   
2. A classic is a book which with each rereading offers as much of a sense of discovery as the first reading.
   
3. A classic is a book which even when we read it for the first time gives the sense of rereading something we have read before.
   
4. A classic is a book which has never exhausted all it has to say to its readers.