A lot of the self-published books I saw at the bookstore had been “edited” in the sense that someone checked the spelling and fixed the commas. That’s worth doing, but it’s one of four quite different jobs, and the other three are where a book gets better.
They happen in a particular order, from the biggest questions to the smallest, because there’s no point polishing a sentence in a chapter that’s about to be cut.
1. Developmental editing
A developmental editor reads the whole manuscript and asks about its shape. Does the argument hold together? Is the book clear about who it’s for? Do the chapters come in the right order? Is chapter four doing anything chapter two didn’t already do? Would a reader have a reason to keep turning pages?
The result is usually a long letter and notes in the margins rather than a marked-up page. It’s the edit authors find hardest to receive and the one that changes a book the most. Most self-published books I saw at the bookstore had skipped it entirely.
2. Line editing
Once the structure is sound, a line editor works through the book sentence by sentence. Is this paragraph clear? Is that word the right one? Does the same point get made three times in two pages? Does the writing sound like the author on a good day? A line edit is where flabby prose gets tightened and where your voice should come through stronger, not flattened.
3. Copyediting
A copyeditor checks the text for correctness and consistency: grammar, spelling, punctuation, capitalization, numbers, Scripture references, whether a name is spelled the same way in chapter one and chapter eleven. Most American book publishers follow The Chicago Manual of Style, and a copyeditor applies it so you don’t have to memorize it.
4. Proofreading
Proofreading is the last look, done on the typeset pages right before printing. The proofreader catches the typo that slipped through, the missing quotation mark, the heading that broke across two pages. By this point little should change, and that’s the idea.
What this means for your book
If your manuscript has only had the fourth kind, it hasn’t really been edited yet. That’s not a criticism. It’s where most first books are, and it’s the reason most publishers employ editors.
At True Bearing Press, books we accept go through developmental and line editing, and a final proofread, at no cost to the author. Angela Ackerman at Writers Helping Writers has a good breakdown with examples of the same passage at each stage, if you’d like to see the difference on the page.