Judd's book remains the most accessible guide for anyone who wants to know more about copyediting for book publishers. Judd provides explanations and short, basic exercises to illustrate the discussions. She also touches on proofreading (which is not the same as copyediting) and on freelancing concerns. Above all, Judd's book is easy to read and practical; I've always found her advice on test-taking in particular to be comforting.

Amy Einsohn's "Handbook" would be the book you'd wade into once you were completely committed to the cause. It's a monster-thick textbook with a truckload of exercises. (I've never personally made it past the first several chapters, but this book didn't come out until I'd already been editing for a very long time. I've never felt a major compulsion to finish it.)

Neither of these books is going to help with computer/on-screen aspects of editing. Because the techniques are so tied to the software, books that have tried to tackle computer editing have gone out of date rapidly. ( )