Books are especially useful for providing background information. When searching for them, try starting with a keyword or two before adding more. Start broad, then slowly narrow. Remember that you may not need to read the entire book; check the table of contents and the index to find the section that is relevant for you.
Take note of books that we have access to outside of SU by toggling the button on the top left of your results list that says "Include non-USMAI results". You can request these titles through Interlibrary Loan. Books coming from other libraries can take anywhere from 3 days to 2 weeks, depending on how far away they are traveling from, so be sure you can wait to receive it!