What Becomes (A Complete) Classic?

There are 1082 books in Peguin’s Classics collection. “The Penguin Collection raises a number of issues, not least being what exactly is a classic? A book few have read, but which remains in print centuries after it was issued? Does a classic have to have had a social impact, say, Sun Tzu’s The Art of War or Walt Whitman’s Leaves of Grass? Must it sell a zillion copies – Judith Krantz’s Scruples and Dan Brown’s The Da Vinci Code would qualify, though neither are in this package – or is a classic defined by the amount of joy it brings to any reader, like the Hi-Lights constituency? Or should a classic be a book that changes the way we read?”