One of my favorite NPR radio shows, “On the Media,” broadcast a show called “Publishing: Adapt or Die,” a few weeks ago. It was compiled from a bunch of interviews with different folks. In one segment, Brooke Gladstone, the co-host [with Bob Garfield], asked Mathew Ingram, a writer at GigaOm, “Fire your editor?” Although quite unrelated, it sparked a thought: What do authors need most, a publisher or an editor? Which makes the book better? Which has the most direct affect on sales?
The answer is obvious: the editor makes all the difference in the world.
Ask ten people what they’re reading – fiction or nonfiction, doesn’t matter – who’s the author or what’s the title, and they’ll be able to tell you one or both. Then ask who published the book. I’ll bet you find, ten times out nine, they will not be able to tell you.
There are several types of editors. We mostly think of an editor as someone who works for a publisher and helps nurse our books through production and into print. Well and good, but the publishing business being what it is today, it isn’t uncommon for the editor to be more of a project manager than an editor who helps shape and refine your manuscript. [Many New York publishers now expect the agent to do this for their authors.] For that, they often turn to an outside editorial resource, either a developmental editor or a copy editor.
If you’re planning to go the self-publishing route, you’ll have to hire your own editor. I recommend you put the Big Bucks into hiring the best you can. The worst thing that can happen to your fledgling book is for readers to find typos, grammatical mistakes, or “word processing errors” as I call them. For example, I just finished reading a novel published by St. Martin’s Press which had over a dozen word processing errors. Clearly, the author ran a spell-check, but either he or it failed to note the difference between “lead” and “led.” In every case, the verb “led” was the correct word choice, but all were spelled “lead.” A human editor would have caught these and many of the other usage errors.
In another novel published by a big New York house, Farrar, Straus and Giroux, the author makes numerous references to things that diverge from reality. For example, a character says he clicks one of the knobs on a toy remote control. The more correct term would be he turns a knob. An editor would catch that, or at least query it. You might think this is a minor thing, but it is not because  the author is portraying a character who is very neat, precise, and diligent, and  it causes the reader to pause or stop reading, which is not desirable. We never want readers to stumble or stop in order to try to figure out what we’re saying.
In the final analysis, you always need an editor of one sort or another. Probably more than one. If you’re going with a publisher, make sure you ask about editing. If you’re going self-publishing, be prepared to seek out the best editor(s) you can find. Remember, this is you, in print.