Well first you should understand the topic and key words.
Regionalism: the theory or practice of regional rather than central systems of administration or economic, cultural, or political affiliation. "a strong expression of regionalism"
Realism: the attitude or practice of accepting a situation as it is and being prepared to deal with it accordingly or the attitude or practice of accepting a situation as it is and being prepared to deal with it accordingly.
After understanding this you can compare and contrast ideas of beliefs, culture and politics in comparison of the attitude of the author or book.