As a professional editor (I do actually get paid to do that, which I think is pretty cool) I thought I knew quite a bit about editing.
Spoiler: I didn't know enough.
There's always more to learn, there's always more to be said, and if I stop learning (if I think there's nothing left for me to learn) then I've officially stopped being good at what I do. Why? Because there's no such thing as no-effort maintenance. If I'm not actively practicing and improving, then I'm getting worse. I think that's true of most skills, if not all of them. So buckle in, Inklings, because I learned something new this week and I want to share it.
For a long time, I thought "copyediting" was just a fancy word for "proofreading." Hoo boy, was I wrong.
A proofreader takes a printed version of your final draft and marks it up for grammar, syntax, punctuation, and spelling errors. They also check for spelling and numerical consistency, so you don't call it a longsword on page 3 and a long sword on page 8. And since it's already printed, they can also point out awkward page- or word-breaks or missing pages or passages, so that in the final print, everything looks as polished as possible.
If there are too many errors, they send it back to the author for a second round of copyediting, because by then this step ought to have already been done.
Where proofreading looks specifically for errors and inconsistencies, copyediting is a bit more like what we might call "revision." It's not just looking for words you typo'd, but it's checking for thematic and narrative consistency, pacing, characterization, and dialogue flow. Copyediting is not just checking for errors, it's making sure your story feels more like one story and less like a series of scenes smashed together because the author wanted them that way.
A good copyeditor is invaluable, and should be hired as a last step before publication, to make absolutely sure that your story is the story you wanted to write, or at least one you would be proud of.
As it happens, copyediting is one of the skills I'm in the process of mastering right now, so this will be a service I offer in the near future.
What do you Inklings think about the multiple kinds of editing available, and are they necessary for a book, or optional?