The Proofread

A proofreader is not supposed to be an editor. Their job is to make the text work at a very fine level of detail. Every comma, semi-colon, dash. Every paragraph has to be indented or not indented just right. It's a job for a very detailed person.

They will make edits if it makes sense to do so to help the sense of a sentence, but it is not their main job. If a proofreader is doing too much copy-editing, they will stop and tell the publisher it needs a copy-edit first.

To send if off the publisher we first had to save it as a Microsoft Word document and then go over everything to make sure the conversion worked as expected. It did for the most part, or so we thought. One thing the Google Docs to Microsoft Word conversion did not handle well is to change the quote marks to be smart quotes instead of a regular straight up and down quote. 
A regular quote mark looks like:  "
A curly opening quote mark looks like: “
A curly closing quote mark looks like: ”

Our proofreader very kindly fixed many of them for us. I use Google Docs for computer code also which require straight quotes, so it is turned off in my version.

The proofreader was also kind enough to note a couple of sections that read awkwardly. These were sections that I was aware off and wasn't sure how well they'd work, so I let a dev editor of the publisher's choosing have a go at it. It wasn't the best choice, but she was able to give me enough feedback where I could rework those sections. It was something of a necessary pain. We actually did a repeat proofread and it's a better book because of the process. It did slip the published date by three months, but it was well worth it.

There were some things that I had to defend more than once. I like chapter titles. Apparently they are out of favor these days. Whatever. I like them and they help me a lot. So after about two go rounds about "Yes, I want to keep them." they stayed.