A book editor is a person who helps writers improve their books by suggesting changes and correcting mistakes in things like grammar and storytelling. Full definition
I've put together an amazingly skilled and experienced team of book editors committed to your publishing success. (thewritersally.com)
Through this, professional book editors for hire are able to notice every shift in language. (changingthescript.com)
Once you've done this, send it on to a professional book editor for a round or two (or three) of developmental editing and then a round of line editing. (magnoliamedianetwork.com)