Books to educate me

I want to educate myself and become a professional like many members of this forum. Can anyone recommend me a couple of books containing information on techniques, chemical, contracts and forms to be used in this type of work.

Pressure Washing Bible

The Pressure Cleaning Bible: Marketing: Proven Secrets of the Pros for Winning Marketing Strategies: Steve Stephens, Allison Hester: 9781453859100: Books

Is this a book you are familiar with? Is it really what it says or just a marketing thing. When you google pressure washing, window cleaning or any business, there are numerous offers with the “best” way to start pressure washing or what ever. They usually fall short of their claims. Just wondering if you’ve read it and is it worth it?

Thanks Phil

Thnks Tino