Joan Didion

What editors do for writers is mysterious, and does not contrary to general belief, have much to do with titles and sentences and "changes".

The relationship between an editor and a writer is much subtler and deeper than that, at once so elusive and so radical that it seems almost parental: the editor, if the editor was Henry Robbins, was the person who gave the writer the idea of himself that enabled the writer to sit down alone and do it.

This is a tricky undertaking, and requires the editor not only to maintain a faith the writer shares only in intermittent flashes but also like the writer, which is hard to do. Writers are only barely likable. They bring nothing to the party, leave their game at the typewriter.
-Joan Didion, After Henry page 20-21