Stet is Latin for “let it stand.” It’s also a word of power for dealing with copyeditors who have — in the author’s opinion — overstepped the limits of their job.
A good copyeditor is the author’s friend. He or she will do things like keeping track of a whole extended family of fictional characters across a multi-volume series, with accompanying fictional place-names and scraps of invented language, so that even if the author fails to do the math and accidentally keeps the same minor character twenty-five years old for almost a decade, the mistake will be fixed before the book hits print. Characters who enter a scene wearing a t-shirt and jeans will not leave it wearing khaki cargo pants and a flannel button-down, unless they’ve been witnessed changing clothes in the interim. The setting sun will not shine in through what can only be an eastward-facing window (if the author has supplied enough detail for a reader to infer the layout of the manor house, a good copyeditor will keep that layout in mind.)
In short, a good copyeditor will make you look smarter than you really are, and will ensure that your book is as good as it deserves to be. If you get a particularly good or face-saving copyedit, it’s a kindness to tell your editor to pass along your thanks to the copyeditor — rather like sending your compliments to the chef — and to mention that if they’re free the next time you have a book come up on the schedule, you’d love to work with them again.
Bad copyedits . . . let’s just say that it’s almost impossible to be a professional writer and not fall victim to at least one staggeringly awful copyedit. Authors gather in bars and tell copyeditor horror stories. (To be fair, the group at the other end of the bar is a gang of copyeditors, telling author horror stories. If no man is a hero to his valet, no author is a hero to his copyeditor.) At times like these, it helps to keep in mind that the book is, in the end, your book, and to remember the magic word.