Start at the top of the copyright page and work your way down. Copyright pages can be formatted differently, but they usually start with the publisher, date, and location of publication. Slowly scan each line to look for an editor’s line listing. The editor (or group of editors) are usually listed in the middle, underneath the publisher’s information, but above the country and printing number.
It’s always sensible to follow due diligence in submitting your first draft of your book to an editor by making as fool-proof a copy as possible for you because first, it is your own creation, and secondly, a horrid draft sent your editor can end up frustrating both you and him or her. Make your own corrections to the extent you can, so that will make the job of your editor that much lighter and the end result would be a lot more effective.