Turn the title page over to find the copyright page. Turn the title page over to find the copyright page. It is usually printed on the back of the title page. The copyright page almost always uses a smaller font than the rest of the book, and is often flush with the bottom margin of the page, instead of the top. It contains publisher information, citation information, the date, locations, and information used to catalogue a text.[2]
Inspect the spine of the book and look for a smaller name under the author. Turn the book over and look at the spine—the thin side of the book where the pages are bound to the cover. If there are multiple names on the spine of the book, they are always ordered with the author’s name first, and the editor’s name after it. On most books, the editor’s name will be smaller so that a passerby can quickly tell who the author is.[5]
Amazing post, Dave, and definitely an important topic. My first book I used one of the larger “editorial agencies” you mentioned. The quality wasn’t bad but there was no direct contact with the editor. Just ship it to them and they ship it back. I’ve tried out several editors now and found a very good one who did a great job on my list book. Once you find a good editor, stick with him/her and build a relationship if you can. Thanks for the list provided and this editors test is a great addition.

I like the idea of embedding “fine print” into the initial email. I also think it’s a good idea for an author to check references; the questions Val suggested are great. Third, as another commenter said, an editor can give the author a general assessment of their book, which will help the author decide if that particular editor will be a good fit or not.

Finding ebooklaunch by surfing the Internet was awesome!!! I used them to format my most recent book "Christian Caregiving: Practical Advice for a Happy Ending" and I am so glad I did. They are fast, efficient, and careful. I will use them again next time I am inspired to write another book. I will also be telling all my author friends about their great service. Five Star!

Software and Systems – Some of us writers like using certain types of writing tools or software.  I personally love to write my books using Scrivener, and will then switch to Google docs for better tracking systems.  However, I've run into editors who only use Word document.  That's no bueno for me.  So, make sure they are good with whatever writing programs you want to use.
An edit is a business transaction. This means that money will exchange hands. Therefore, you need to approach the edit as both a writer and a businessperson (an increasingly common role in the age of self-publishing). Compare the deals you’re offered. Editors with brand-name backgrounds might offer less user-friendly terms (such as hourly rates, which are less predictable than fixed contracts), while less established professionals might offer discounts and extras (such as book formatting and publishing consulting). Don’t be afraid to ask. Hiring an editor is a professional investment. A sample edit will allow you to estimate the value of the service, but never forget about the price.
In return for the sacrifices you must make in order to self-publish, you will gain total control over the project. In addition, any profits from sales of the book will be yours (not just a royalty percentage as with either a traditional publisher or a vanity press), and in some cases it may be the only way of getting your book into the hands of readers. However, there is no getting around the requirement to get the tasks done one way or another.

Regarding your last question, I know of no editor who gives a money-back guarantee for occasional errors that happen to slip through or for a different opinion by a later editor. I’m afraid such things are just the nature of the publishing beast. But by having a shorter portion edited first, you will get a decent feel for whether someone is the right editor for you, and will be able to be confident in his or her work on your entire book.