You can find books in Summon by typing in a title, author, or topic, then using the limiters next to your search results to narrow your results to just books. The video below shows great tips for using Summon.
The BGSU Library Catalog can also be used to find books. This is sometimes a better way to search for books by topic, because
Just a few to try. Search for "film" and "encyclopedias" or "film" in main reference for more options.