For my book, Career Change, I gave an early copy to people working in my department in the day job who I knew were dissatisfied with what they were doing. They came back with questions and suggestions for what to include as additional material. For The Healthy Writer, we asked medical doctors to read it as a sense check (even though my co-writer, Euan Lawson, is a doctor!)
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.