A reader recently congratulated me on having a book with “zero mistakes” compared to others she’s recently read. (No, this is not a challenge for anyone to seek out a mistake and prove her wrong. You will only make me cry.)

I’m delighted that that was her experience of my book, and I sympathize with her frustration with what looks like laziness. When one finds an obvious grammar or spelling error in a published book, it reflects not only on the author, but on all those who read it and worked on it along the way. Not only did the author create the mistake; everyone else missed it!

But that, in my experience, is not actually where mistakes come from. I make few mistakes when writing from start to finish. (With the embarrassing exception that, in my current manuscript, I wrote manner instead of manor; shocking! My excuse is that I was sleep-deprived. And, it was caught by every person who’s looked at it–thanks, guys!)

The big mistakes start when I look at small pieces of the story in isolation. Once a scene, or paragraph, or sentence, is divorced from the whole for the purpose of editing, mistakes are easy to make. At that point, they are also terribly difficult to recognize. Once you’ve read something a dozen times, you see what you expect, not necessarily what is.

Here’s an example: I sent an email invitation that originally had two events on it, and then added a third. One sentence originally read:

“Please let me know if you plan to make either of these two films.”

I corrected that sentence by changing the “two” to “three”:

“Please let me know if you plan to make either of these three films.”

Which is now wrong, because I didn’t notice to change “either” to “any.” I would never write “either of these three.” But it’s easy to end up with it when I edit bits and pieces.

So if you do find a mistake in a book, chances are it crept in later in the process, when the manuscript as a whole was already past most readers, and it was just the author and editor, working on it piecemeal.