How old do a classic book have to be to be a classic book?

Answer:
Classic books are like cult movies. They shape new concepts in our society, have something special to offer in an educational way. It is more these aspects of a book that make it a classic.. not how long ago it was published.
First answer by Leticiajw. Last edit by Gvanhuyssteen. Contributor trust: 3 [recommend contributor recommended]. Question popularity: 3 [recommend question].