According to Flavorwire, here are the thirty harshest author-on-author insults in history. Truth is they are incredibly clever. But I cannot believe that this is all. I'm sure there are others that are even more devastating. Even more witty.
An quick example from the list:
15. William Faulkner on Ernest Hemingway
“He has never been known to use a word that might send a reader to the dictionary.”
14. Ernest Hemingway on William Faulkner
“Poor Faulkner. Does he really think big emotions come from big words?”
Enjoy. At least they're not saying those things about you. Or, on the other hand, maybe it's too bad that they're not.