Your assignment requires you to use books as sources. that means you need to that add to what you know and understand about your topic ... and that means you can cite the book in your paper when you only use a chapter or a section. Use the and/or the to find just those most useful sections of the book.
Skim the index from A-Z. Let you eye rest on any word or phrase that seems related to your topic. This might be a direct connection or not. Check the pages to see if the text adds to your knowledge of your topic. Read a bit before and a bit after the exact page(s) listed in the index. Be thorough.