Here are some questions to get you started in thinking about non-fiction books:
What themes seemed, to you, to be a concern the author had in writing the book?
Which part of the book did you find most interesting, and why?
Has this book changed how you think about the subject?
What new things did you learn from this book?
After having read the book, what did you want to know more about?
Did you enjoy the prose style in the book? Why or why not?
What other books or authors would you recommend on this subject?