Book editing is both subjective and not. There are rules, and yet the rules of writing are often intentionally broken. You want to find someone who knows the rules, who will fix the writing, and who’s flexible enough to know that voice is sacrosanct, and that editing out colloquialisms, slang, and humor is a no-no (unless it’s overdone or not working, that is).
Use the Library of Congress database to find publication information. The Library of Congress is the national library of the United States, and has one of the largest databases of books in the world. Go to https://www.loc.gov/ and click the search bar. Type in the name of the book and the author’s name if you have it. Scroll through the results until you see the version of a book that you’re looking for. Click the title to open the book’s informational page and look for the editor.
In addition to the individual editors listed above, the Reedsy marketplace is full of vetted professional editors for every editing level and genre. They screen their editors and only allow the best of the best to be listed on their website. I'm a BIG fan of them because they have made the process easy for me to find the best book editors, book cover designers, and even writers to help me with my projects. Talk about awesome!
What an editor does is discover your characters, your situations, and your images without seeing any of the creative process that brought them to life. Where you might see all the crossings-out and labors, all the accidents and decisions, the editor sees only a page. This is the clarity you need, and you can never achieve it for your own writing, simply because you envisioned it first. The editor will tell you what an attentive, an educated, and, most importantly, a new reader will experience while reading your book.
While you may (or may not) be correct in your assumptions, your tone in general is rude, and disrespectful. If you are indeed a true editor of distinct taste and experience, you should not feel the need to bad mouth others for their thoughts and opinions. Show a little decency, and realize that you are indeed speaking to a human being, who probably has thoughts and feelings, and is in my opinion, a much more intelligent human for having the intellect to not attack someone verbally for their thoughts. No one needs you to be rude, or asked you for that matter.
Hm, I’m a longtime freelance book editor and have a few thoughts to share. I think one page of editing is not enough to gauge much, and that you should be able to get a sample edit of 10 (double-spaced 12-point) pages from a potential editor. You’ll have a better idea after a complete chapter has been edited, and you should have a contract that allows either you or the editor to opt out cleanly at various stages. Another thought: sometimes authors don’t know what level of edit they need, and a good editor can assess this based on reading a few pages of your ms. and spot-checking the remainder. Also: a lot of book editors (like me) work primarily for publishers rather than for individuals. It’s just easier. I know I’ll get paid, I don’t need to educate publisher clients about the process itself, and they send me regular work, so we get to know each other’s needs and preferences. Lastly, I wouldn’t really expect a newcomer editor to be able to handle a booklength manuscript very well (I was that person once — eek). If it’s someone really new, they should have had good training somewhere imo. Book editing is a technical undertaking. It’s also about knowing what to leave alone. Inexperienced people often tamper with authors’ work unnecessarily. Anyhow, I’d be happy to answer any questions.
I implemented this way of working years ago and see how empowering it is for authors, and helpful for editors to boot. This doesn’t mean you’re asking your editor to do a free sample edit. (I discourage editors from doing this and caution authors who push for it as asking editors to work for free before you hire them may result in resentment.) Paying an editor for a few hours of their time to ascertain whether they’re a good fit for you is a great way to put your toe in the pond before submerging yourself. You can then see for yourself if the editor’s suggestions and comments resonate before moving forward with the whole project.