What does an editor do?

Been a busy month or so. Spent two weeks wandering around Europe, and worked through the beta-reader edits on my next novel. Just sent it off to my professional editor yesterday, and that means we may see a final product around the beginning of August. You guys may get your hands on this book yet.

Just as I did shove my book out of its protective little nest, I ran across this terrific breakdown of how to pick an editor from the endlessly helpful Shayla from Curiouser Editing. It really goes...