If you mention a company or organization name in your book, do you have to get the permission of each before publication?
Generally no. Most companies welcome free publicity. However, it’s imperative that they are shed in a positive light, if not you can face a lawsuit.
My advice would be when in doubt contact the company in question for permission and outline exactly in what capacity you will be mentioning them.
I would go so far as to say that if they agree verbally, get it in writing. That way, the company in question cannot say they didn’t give consent once your book is published.