I remember that the single most vicious letter I ever read was the letter Hemingway wrote Scribners when they asked him to give a blurb for From Here to Eternity. It's there, in the Selected Letters for all to read, an example of a once great writer at his very worst. I doubt that he ever forgave Scribners for publishing James Jones in the first place. War, as Hemingway saw it, belonged to him.
