I recently completed a grueling two days going over copyedits for my upcoming book on medieval handgonnes for Osprey Publishing. The copyeditor was the most meticulous person I've ever worked with, and her long list of queries, changes, and suggestions took ages to get through.
She didn't just look for grammatical and spelling errors, of which there were few since I write pretty clean copy, but researched the subject and asked me about alternative spellings to medieval names and competing theories that she felt I didn't cover enough. She also had the habit of finding every possible alternate meaning to a statement and making me change them so that they weren't just clear to me (and her) but to the thickest possible reader. That doesn't mean she wanted the book dumbed down, simply made crystal clear.
I didn't mind, because it's nice to know other people care about the project! In fact, everyone at Osprey cares about the project. The series editor answers my emails in a timely fashion (a rarity in publishing), the layout people are doing a fine job, and the artist has made two beautiful paintings. Like my book on Civil War guerrillas, the handgonnes book is getting full-color artwork painted by Gerry Embleton. I'll talk more about his work when we get closer to publication in October. Suffice it to say that fans of military artwork are in for a treat.
This is how publishing should be--a team effort. Too often someone drops the ball. Either the copyeditor is over worked and underpaid, or the layout people don't read instructions about what photos should go where, or the marketing people don't market. The Osprey folks actually care about their job and do it right. This has not always been my experience in earlier stages of my career, so working at Osprey is a pleasure. Exhausting, but a pleasure.