Some of them are very good books, others just seem like an interesting change of pace.
Call of the wild by Jack London,
Invisible man by Ralph Ellison,
Deliverance by James Dickey,
Even the Grapes of Wrath (John Steinbeck) made it on there. (Sure, it's listed as being 'all about the titty', but it's still there)
Take a look, how many have you read?