Copyediting and proofreading are major, non-interchangeable steps in the book writing process.
What’s the difference between the two?
Copyeditors improve the text, while proofreaders ensure mistakes don’t make it into the finished product.
You need a copyeditor to “clean up” your finished manuscript and make certain it observes the conventions of good writing – appropriate grammar, accurate word choice, smooth syntax and correct punctuation. A good copyeditor will also point out any gaps in information or lapses in logic, identify repetitious material, ask questions when information/explanations are unclear, and may suggest cuts. Copyediting, in short, is about revising/improving your manuscript in order to bring it up to publishable standards. Since it is impossible to be totally objective about your own manuscript, a good copyeditor is absolutely essential.
Once your manuscript has been copyedited and all of the copyeditor’s queries have been addressed, it goes to a proofreader, who will look for typos, misspelled words and grammatical mistakes. Proofreaders also ensure uniformity in font, type size and heading styles, and see that captions match their diagrams or photographs. Proofreading, then, is about looking for mistakes in the manuscript and ensuring that they don’t end up in the finished product. It’s usually necessary to proof a manuscript twice – once before submitting it to the publisher and then again when you receive the galley proofs. (Somehow, plenty of mistakes – sometimes new ones – manage to appear in many galley proofs!)
A good copyeditor and a competent proofreader play invaluable roles in the production of a book that is polished, professional and a pleasure to read. Skimping at this point in the process is a critical mistake – it can erode your authority, devalue your message and severely undercut the impact of your book.