William Faulkner on Mark Twain (1922)

“A hack writer who would not have been considered fourth rate in Europe, who tricked out a few of the old proven sure fire literary skeletons with sufficient local color to intrigue the superficial and the lazy.”

Mark Twain on Jane Austen (1898)

“I haven’t any right to criticize books, and I don’t do it except when I hate them. I often want to criticize Jane Austen, but her books madden me so that I can’t conceal my frenzy from the reader; and therefore I have to stop every time I begin. Every time I read ‘Pride and Prejudice,’ I want to dig her up and hit her over the skull with her own shin-bone.”

http://flavorwire.com/188138/the-30-harshest-author-on-author-insults-in-history