Proofreading is a cold-reading process that hunts down and eliminates last-minute typos before a book goes to press.
Have you ever written an email or text and, as soon as you press send, notice the typo? It’s something that happens to all of us. You see what you wrote, not actually what you literally wrote.
It’s an even bigger problem when you are writing and revising something that YOU wrote. Your brain naturally focuses on the high-level issues, like plot progression, structure, or the central argument, and in doing so, misses the little things. It’s easy to skip over those little mistakes because your brain is focused on what it thinks really matters.
Proofreading is the final polish of your book before it is published, and is recommended only for previously copy edited manuscripts. This ensures that your book is free of errors.