authorship - What exactly is an editor?

I recently read the assertion that many great works of fiction were chiefly down the contribution of a good editor. I must admit I was a little taken aback by this statement. I had never really thought of the writer and editor as being like the musician and producer. To what degree is this really true?

I always liked to think that as the author I am the writer and the "producer" of my story an editor is just there to clean syntax glitches and polish spelling (they are also free to point out bits of the story they don't like but surely in most cases this is a matter of opinion). If I were to read the work of others and tell them "x doesn't work" I feel I'd probably get a bunch of abuse. I try always to appraise work as "I feel this is currently a problem because..." or "this would work better if..." I always think of this as critique, is this editing?

I guess this question comes down to "What is an editor? How would one know a good one? What behaviour from an editor is appropriate?"

Answer

There are different levels of editing which are lumped together under the same term, which might be what's confusing you.

"Syntax glitches and spelling" is line editing, aka proofreading, sometimes called copyediting. Similar to this is fact-checking, where the editor is looking up anything based in reality or researching anything made up for plausibility.

Pointing out things which don't work in terms of plot, character, setting, world-building, etc. is content editing, also called developmental editing. Whether phrased nicely as a suggestion or bluntly as a direction, the editor is saying that something about the story itself has to be changed. (This is what you're calling "critique," which isn't totally inaccurate, but critiquing leans more towards style and less towards mechanics.)

The assertion which you heard refers to the idea that a writer and editor (one single editor) work together over multiple drafts to shape a book. The writer is the person coming up with the main idea, the plot, the characters, and the actual words. The editor points out what is and isn't working, suggests moving this bit to over there in that chapter, points out where foreshadowing could be inserted, objects to out-of-character behavior, and chops out chunks of unnecessary narration (among other things).

A good editor is someone who works with you, someone who respects your style and your ideas but pushes you to improve. Speaking as both a writer and an editor, I think what goes on the page is ultimately the writer's privilege and responsibility. So an editor's job is to suggest, and make arguments in support of suggestions, but the writer gets the final decision.