To find books and government documents in USA Libraries' collections, use SOUTHcat: USA Libraries' Catalog.
Subject encyclopedias have a wealth of background information that can provide you with a strong foundation upon which to build your research. To find a subject encyclopedia, try the search strategies shown in this tutorial or try a keyword search in SOUTHcat for the subject and the word encyclop?
Example: To find a communication encyclopedia, do a SOUTHcat keyword search for encyclop? communication?